U.S. patent application number 13/864062 was filed with the patent office on 2013-08-29 for coating composition comprising autoxidisable component.
This patent application is currently assigned to DSM IP ASSETS B.V.. The applicant listed for this patent is Gerardus Cornelis OVERBEEK, Ronald TENNEBROEK, Ilse van CASTEREN, Jelle Bernardus Otto van der WERF. Invention is credited to Gerardus Cornelis OVERBEEK, Ronald TENNEBROEK, Ilse van CASTEREN, Jelle Bernardus Otto van der WERF.
Application Number | 20130225724 13/864062 |
Document ID | / |
Family ID | 39654884 |
Filed Date | 2013-08-29 |
United States Patent
Application |
20130225724 |
Kind Code |
A1 |
OVERBEEK; Gerardus Cornelis ;
et al. |
August 29, 2013 |
COATING COMPOSITION COMPRISING AUTOXIDISABLE COMPONENT
Abstract
There is described (pref. non-adhesive) coating compositions
(which may be either water or solvent borne) that comprise an
autoxidisable vinyl polymer, the autoxidisable polymer having a
vinyl polymer backbone 25% to 75% by wt of the autoxidisable
polymer; fatty acid residue 25% to 75% by wt of the autoxidisable
polymer; T.sub.g from -60.degree. C. to +20.degree. C., M.sub.w
from 3500 to 50000 g/mol; and polydispersity from 2 to 10; the
autoxidisable polymer obtained by a process of: (A) polymerising
ethylenically unsaturated vinyl monomers comprising: at least one
epoxy functional vinyl monomer 15% to 100% by wt total monomers in
(A); 0 to 85% of at least one other ethylenically unsaturated vinyl
monomer, (preferably other than styrenic monomers) by wt total
monomers in (A); (B) reacting the epoxy functional polymer from (A)
with fatty acids having an average iodine value from 30 to 250 g
I.sub.2/100 g fatty acid; where composition has: a) a opt.
co-solvent content 40% by wt of the composition; b) a solids
content either 30% (aqueous) 60% (solvent based) by wt of the
composition, the composition as a coating film having a
telegraphing value of less than 10 gloss units (difference between
an initial smooth gloss minus an initial rough gloss of the
film).
Inventors: |
OVERBEEK; Gerardus Cornelis;
(Waalwijk, NL) ; van CASTEREN; Ilse; (Waalwijk,
NL) ; TENNEBROEK; Ronald; (Waalwijk, NL) ; van
der WERF; Jelle Bernardus Otto; (Zwolle, NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OVERBEEK; Gerardus Cornelis
van CASTEREN; Ilse
TENNEBROEK; Ronald
van der WERF; Jelle Bernardus Otto |
Waalwijk
Waalwijk
Waalwijk
Zwolle |
|
NL
NL
NL
NL |
|
|
Assignee: |
DSM IP ASSETS B.V.
Heerlen
NL
|
Family ID: |
39654884 |
Appl. No.: |
13/864062 |
Filed: |
April 16, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12920386 |
Dec 6, 2010 |
|
|
|
PCT/EP2009/053830 |
Mar 31, 2009 |
|
|
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13864062 |
|
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Current U.S.
Class: |
523/410 ;
427/386 |
Current CPC
Class: |
C08F 8/14 20130101; C08F
8/44 20130101; C08F 220/28 20130101; C08F 8/14 20130101; C08F
120/06 20130101; C08F 220/325 20200201; C08F 220/14 20130101; C08F
212/08 20130101; C09D 133/068 20130101; C08F 220/325 20200201; C08F
2810/30 20130101; C08F 8/14 20130101; C08F 8/14 20130101; C08F
212/08 20130101; C08F 220/32 20130101; C08F 220/325 20200201; C08F
220/325 20200201; C08F 2810/50 20130101; C09D 133/14 20130101; Y10T
428/31855 20150401; C08F 220/14 20130101; C08F 8/44 20130101; C08F
220/325 20200201; C08F 220/1804 20200201; C08F 212/08 20130101;
C08F 220/1804 20200201; C08F 220/1804 20200201; C08F 220/1804
20200201; C08F 220/325 20200201 |
Class at
Publication: |
523/410 ;
427/386 |
International
Class: |
C09D 133/14 20060101
C09D133/14 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2008 |
EP |
08006275.5 |
Claims
1. A coating composition that comprises an autoxidisable vinyl
polymer, said composition being selected from the group consisting
of aqueous coating compositions and solvent-based coating
compositions, where; I) said autoxidisable vinyl polymer has: i)
vinyl polymer backbone in an amount from 25% to 75% by weight of
said autoxidisable vinyl polymer; ii) fatty acid residue in an
amount from 25% to 75% by weight of said autoxidisable vinyl
polymer; iii) a T.sub.g from -60.degree. C. to +20.degree. C., iv)
a weight average molecular weight (M.sub.w) from 3,500 to 50,000
g/mol; and v) a PDi from 2 to 10; II) said autoxidisable vinyl
polymer is obtained or obtainable by a process comprising the steps
of: (A) polymerising ethylenically unsaturated vinyl monomers
comprising: i) at least one epoxy functional vinyl monomer in an
amount from 15% to 100% by weight of the total monomers in step
(A); and ii) at least one other ethylenically unsaturated vinyl
monomer in an amount from 0% to 85% by weight of the total monomers
in step (A); to obtain an epoxy functional vinyl polymer (B)
reacting said epoxy functional vinyl polymer obtained in step (A)
with fatty acids having an average iodine value from 30 to 250 g
I.sub.2/100 g fatty acid; and III) said composition has: a)
optionally a co-solvent content less than or equal to 40% by total
weight of said composition; b1) when aqueous has a solids content
greater than or equal to 30% by total weight of said aqueous
composition; b2) when solvent-based has a solids content greater
than or equal to 60% by total weight of said solvent-based
composition; and IV) said composition when in the form of the film
has a telegraphing value of less than 10 gloss units, where the
telegraphing value is the difference between an initial smooth
gloss value minus an initial rough gloss value of the film, where
the initial smooth gloss value is the gloss when the film is cast
on smooth PVC (R.sub.z=1 .mu.m [.+-.0.25 .mu.m]); the initial rough
gloss value is the gloss when the film is cast on rough PVC
(R.sub.z=25 microns [.mu.m] [.+-.5 .mu.m]); and where each film has
a dry film thickness of 52 .mu.m [.+-.6 .mu.m]; and each initial
gloss value is measured at a 20.degree. angle, one day (24 hours)
after the film has been cast.
2. A coating composition according to claim 1, which is a
non-adhesive composition.
3. A coating composition according to claim 1, in which the epoxy
functional vinyl polymer prepared in step (II)(A) has a M.sub.n
from 1,500 to 10,000 g/mol.
4. A coating composition according to claim 1, in which the epoxy
functional vinyl polymer prepared in step (II)(A) comprises 0 to 1%
of acid functional vinyl monomers by weight of the epoxy vinyl
functional polymer.
5. A coating composition according to claim 1, in which the epoxy
functional vinyl polymer prepared in step (II)(A) comprises less
than 5% of hydroxy functional monomer(s) by weight of the epoxy
vinyl functional polymer.
6. A coating composition according to claim 1, in which the epoxy
functional vinyl polymer prepared in step (II)(A) comprises less
than 40% of styrenic monomer(s) by weight of the epoxy vinyl
functional polymer.
7. A coating composition according to claim 1, in which the fatty
acid residue is substantially free of fatty acid glycidyl
esters.
8. A coating composition according to claim 1, which is
aqueous.
9. An aqueous coating composition according to claim 8, comprising
no more than 13% N-methylpyrrolidone by weight of the total
composition.
10. An aqueous coating composition according to claim 8, comprising
no more than 13% of nitrogen containing molecules with an
evaporation rate <0.1 the molecules being aromatic, heterocyclic
or aliphatic primary and secondary di-amines where the weight % of
nitrogen is >5% by weight of the molecule.
11. A coating composition according to claim 1, which is solvent
based.
12. A process for obtaining a polymer that contains at least one
autoxidisable vinyl polymer where: said autoxidisable vinyl polymer
is capable of forming a coating composition that when in the form
of the film has a telegraphing value of less than 10 gloss units
(as defined in claim 1); the process comprising the steps of: I)
polymerising ethylenically unsaturated vinyl monomers comprising:
i) at least one epoxy functional vinyl monomer in an amount from
15% to 100% by weight of the total monomers in step I); and ii) at
least one other ethylenically unsaturated vinyl monomer in an
amount from 0% to 85% by weight of the total monomers in step I);
to obtain an epoxy functional vinyl polymer; and II) reacting said
epoxy functional vinyl polymer obtained in step I) with fatty acids
having an average iodine value from 30 to 250 g I.sub.2/100 g fatty
acid; where the resultant autoxidisable vinyl polymer has i) vinyl
polymer backbone in an amount from 25% to 75% by weight of said
autoxidisable vinyl group containing polymer; ii) fatty acid
residue in an amount from 28% to 75% by weight of said
autoxidisable vinyl polymer; iii) a T.sub.g from -60.degree. C. to
+20.degree. C., iv) a weight average molecular weight (M.sub.w)
from 3,500 to 50,000 g/mol; and v) a PDi from 2 to 10.
13. A polymer obtained and/or obtainable by a process as claimed in
claim 12.
14. A coating composition comprising a polymer as claimed in claim
13.
15. A coating obtained and/or obtainable by a coating composition
as claimed in claim 1 and having a telegraphing value (as defined
in claim 1) of less than 10 gloss units.
16. A substrate coated with a coating as claimed in claim 15.
17. A method of coating a substrate comprising the steps of i)
applying a coating composition as claimed in claim 1 to a
substrate; ii) drying the substrate to form a coating thereon;
where the coating has a telegraphing value (as defined in claim 1)
of less than 10 gloss units.
18. Use of an autoxidisable vinyl polymer and/or a coating
composition as claimed in claim 1, for the purpose of obtaining
coatings having a telegraphing value (as defined in claim 1) of
less than 10 gloss units.
19. A method of manufacture of an autoxidisable vinyl polymer
and/or a coating composition as claimed in claim 1, for the purpose
of obtaining coatings having a telegraphing value (as defined in
claim 1) of less than 10 gloss units.
Description
[0001] This application is a continuation of copending U.S.
application Ser. No. 12/920,386, filed Dec. 6, 2010 (now
abandoned), which is the national phase application of
international application PCT/EP2009/053830, filed Mar. 31, 2009
which designated the U.S. and claims benefit of EP 08006275.5,
dated Mar. 31, 2008, the entire contents of each of which are
hereby incorporated by reference.
[0002] The present invention relates to certain coating
compositions that comprise an autoxidisable component and processes
for making such compositions. Coatings of the invention show
reduced telegraphing of surface irregularities after the
composition has been applied to a surface.
[0003] There is a general need when applying a decorative or
protective coating to a substrate to obtain a smooth surface
without visible irregularities. The degree to which an underlying
surface can be visually ascertained through a coating is often
described as telegraphing (i.e. giving a clumsily obvious hint or
premature indication of something to come). It has been found that
irregularities on substrates (such as wood), which contribute to
the roughness, are often telegraphed through conventional dry
coatings.
[0004] Thicker coating materials are often used to reduce
telegraphing because they are sufficiently able to level out any
unevenness in the surface. Thus the underlying surface roughness of
the substrate shows through to a reduced extent into the final
coating which appears visually smooth. However, thicker coatings
are disadvantageous because they may need to be applied in several
layers, increasing the cost. Also slower through-drying, wrinkling
and sagging can occur when using thicker layers.
[0005] Organic solvents have been used to reduce telegraphing.
However with a continuing concern about the use of organic solvents
there has been a long felt need for an aqueous coating composition
with comparable properties to those achievable using compositions
based on organic solvents.
[0006] A coating should also dry sufficiently quickly to avoid the
adherence of dust and to ensure that the coating quickly becomes
water resistant (e.g. in case of outdoor applications), blocking
resistant and tack-free.
[0007] Aqueous compositions such as water dilutable autoxidisable
esters (also known as water dilutable unsaturated alkyds or alkyd
emulsions) have also been used to address the issue of
telegraphing. However these systems have many well known
problems.
[0008] Water dilutable alkyds may also suffer from backbone
hydrolysis. This may lead to changes in the performance over time
which is undesirable. Traditional alkyd emulsions are discussed in
"Water borne and solvent based alkyds and their end user
applications" by N. Tuck, volume VI, Wiley/Sita Series In Surface
Coatings technology; (ISBN 471985910) published in 2000.
[0009] Another common problem of traditional alkyd emulsions is
their tendency to produce cissing (also known as crawling) when
applied as an over-coat. Cissing is when a coating refuses to form
a continuous film, recedes from the surface, collects in beads and
leaves the surface partially exposed thus reducing the appearance
of the painted object.
[0010] Yet another disadvantage of traditional alkyd systems,
especially those containing a relatively high percentage of
unsaturated fatty acid residues, is their pronounced tendency to
yellow (in light or dark) over time.
[0011] Current coatings lack some or all of the above mentioned
performance characteristics, so coatings which exhibit reduced
telegraphing with a combination of: minimal hydrolysis of the
backbone of the alkyd, low yellowing over time and/or reduced
cissing are desired.
[0012] Prior aqueous coatings have not been widely accepted in many
markets as alternatives to solvent based coatings. For example
solvent based alkyds are still preferred in the decorative market,
where very low telegraphing is required as these coatings are often
applied by brush. It is also desired that aqueous compositions are
not milky or opaque but clear or transparent.
[0013] It is also generally known that polyester based alkyds (PE
alkyds) typically have a broad molecular weight distribution and
thus comprise a significant amount of material having a low
molecular weight, which dries more slowly and therefore means the
coating remains tacky for a longer period (i.e. has long tack free
times). The presence of material of lower molecular weight cannot
be avoided for many reasons. For example both glycerol (with three
fatty acids--triglycerides) and pentaerythritol (with four fatty
acids) are common raw materials used to prepare PE alkyds. To
address the issues raised by the presence of the low molecular
weight fraction, PE alkyds may be prepared in a highly branched
form to obtain a high molecular weight fraction that dries more
quickly. However the resultant branched PE alkyds have a
significantly increased viscosity and reduced flow (compared to
less branched equivalents) and thus must be diluted with more
organic solvent before they can be used. This is undesirable as for
example it increases the amount of volatile organic compounds (VOC)
and adversely affects the flow of the composition.
[0014] It is known that autoxidisable vinyl polymers may be
prepared by a radical polymerisation of vinyl monomers in the
presence of a fatty acid derivative. However the resultant polymers
have a broad molecular weight distribution, and these polymers
require higher amounts of solvent to make a coating, which
generally also contains high levels of free monomer. Without
wishing to be bound by theory it is believed that unsaturated fatty
acids retard radical polymerisation and graft onto the vinyl
polymer resulting in more material of higher molecular weight and a
broader molecular weight distribution.
[0015] WO 2002-033012 (=EP 1328594) (Avecia) discloses an aqueous
coating composition based on a cross-linkable water-dispersible
vinyl oligomer and optionally a dispersed polymer. The oligomers
described in this application have a low amount of fatty acid
(<40% by weight). As shown by the comparative data herein these
oligomers are designed for a different purpose (improved open time)
and produce coatings which, within a few days, lack satisfactory
body (in the tests as defined herein), do not produce satisfactory
tack free times.
[0016] U.S. Pat. No. 5,089,342, EP 0370299 and EP 0316732 (all
Bayer) disclose an aqueous, air drying coating composition
containing a water-soluble, air-drying polyacrylate with a
molecular weight of more than 1000 g/mole and 5 to 40% by weight of
chemically incorporated fatty acids and 50-100 milli-equivalents
per 100 grams of solid of chemically incorporated quaternary
ammonium moieties. This reference describes systems that are
cationic, teaching away from using anionic systems (e.g. see col.
1, line 53) and teaches use of styrenic monomers as part of the
vinyl monomers which is not ideal as it can cause yellowing in the
final product.
[0017] DE 10106561 (Kansai Paint) describes coating compositions
obtained from silicone modified vinyl copolymers with a fatty acid
component.
[0018] WO 02/18456 (Johnson Polymer) discloses a continuous process
for producing polymers having at least one functional group. This
first polymer is transferred to second reactor zone together with
at least one modifier which is complementary to the functional
group.
[0019] U.S. Pat. No. 4,727,100 (Du Pont) discloses a solvent-borne
coating composition containing a reactive urethane component, an
acrylic fatty acid drying oil resin and a metallic catalyst.
[0020] U.S. Pat. No. 6,509,417 (Lilly) discloses a glossy coating
composition comprising 20 to 80% of a solvent and 20 to 80% of a
reactive binder (by weight of composition): comprising (by weight
of binder): A) 0 to 24% of an anhydride acrylic polymer having at
least two reactive anhydride groups and B) 5 to 50% of a fatty acid
modified glycidyl polymer having hydroxy functionality, at least
two reactive glycidyl groups and at least two unsaturated groups
and C) 5 to 60% of a polymeric compound containing multiple hydroxy
groups.
[0021] U.S. Pat. No. 7,235,603 (Rohm and Haas) discloses a method
of preparing an ambient curable aqueous dispersion comprising the
steps of A) preparing polymer particles having one or more stages
by preparing a first stage polymer containing at least one epoxy
group and at least one pendant ethylenically unsaturated side
chain. This polymer is prepared by 1) preparing a precursor polymer
containing at least one epoxy group by free radical addition
polymerization of at least one ethylenically unsaturated monomer
and 2) reacting the precursor with co-reactive olefinic material.
This document describes fatty acid functional acrylic polymers of
low fatty acid content (<40% by weight) which are prepared by
introducing the fatty acid functional groups in the water
phase.
[0022] GB 767476 (Canadian Industries) discloses a resinous
material which is the heat reaction product of a styrene/glycidyl
methacrylate copolymer and an oil acid.
[0023] JP 60110765 discloses the reaction of copolymer of an
.alpha.,.beta. (alpha, beta) unsaturated acid, such as acrylic acid
and other monomers with a glycidyl ester of unsaturated fatty acid
to form a resin which is combined with a second resin to give a
thick aqueous coating.
[0024] We have now found ways to overcome the above mentioned
disadvantages, especially when combinations of more then one of the
problems need to be overcome in one coating system.
[0025] It is an object of the invention to solve some or all or the
problems identified herein. A preferred object of the invention
provides a method of improving the appearance of coated substrates,
the substrates containing visual irregularities. In a more
preferred object of the invention the method can be used with a
wide variety of coating compositions.
[0026] The applicant has found that certain vinyl polymers prepared
by radical polymerisation of certain vinyl/acrylic monomers may
comprise significantly less low molecular weight fraction (like the
aforementioned triglycerides) avoiding the need to use significant
amounts of high molecular weight material, for example to improve
drying. The applicant has also surprisingly found that certain
vinyl polymers (with specific molecular weight, PDi and T.sub.g
values), that are prepared by radical polymerisation of epoxy
functional vinyl monomers with other vinyl monomers, and then
reacted with certain unsaturated fatty acids may overcome some or
all of the above identified problems with prior art vinyl
polymers.
[0027] Therefore broadly according to the present invention there
is provided a coating composition that comprises an autoxidisable
vinyl polymer, said composition being selected from the group
consisting of: aqueous coating compositions and solvent-based (also
known as solvent borne) coating compositions, where; [0028] I) said
autoxidisable vinyl polymer has: [0029] i) vinyl polymer backbone
in an amount from 25% to 75% by weight of said autoxidisable vinyl
polymer; [0030] ii) fatty acid residue in an amount from 25% to 75%
by weight of said autoxidisable vinyl polymer; [0031] iii) a
T.sub.g from -60.degree. C. to +20.degree. C., [0032] iv) a weight
average molecular weight (M.sub.w) from 3,500 to 50,000 g/mol; and
[0033] v) a PDi from 2 to 10; [0034] II) said autoxidisable vinyl
polymer is obtained or obtainable by a process comprising the steps
of: [0035] (A) polymerising ethylenically unsaturated vinyl
monomers comprising: [0036] i) at least one epoxy functional vinyl
monomer in an amount from 15% to 100% by weight of the total
monomers in step (A); and [0037] ii) at least one other
ethylenically unsaturated vinyl monomer in an amount from 0% to 85%
by weight of the total monomers in step (A); to obtain an epoxy
functional vinyl polymer; [0038] (B) reacting said epoxy functional
vinyl polymer obtained in step (A) with fatty acids having an
average iodine value from 30 to 250 g I.sub.2/100 g fatty acid; and
[0039] III) said composition has: [0040] a) optionally a co-solvent
content less than or equal to 40% by total weight of said
composition; and [0041] b1) when aqueous, has a solids content
greater than or equal to 30% by total weight of said aqueous
composition; [0042] b2) when solvent-based, has a solids content
greater than or equal to 60% by total weight of said solvent-based
composition; and [0043] IV) said composition when in the form of
the film has a telegraphing value of less than 10 gloss units,
[0044] where the telegraphing value is the difference between an
initial smooth gloss value minus an initial rough gloss value of
the film, where [0045] the initial smooth gloss value is the gloss
when the film is cast on smooth PVC (R.sub.z=1 .mu.m [.+-.0.25
.mu.m]); [0046] the initial rough gloss value is the gloss when the
film is cast on rough PVC (R.sub.z=25 microns [.mu.m] [.+-.5
.mu.m]); and where [0047] each film has a dry film thickness of 52
.mu.m [.+-.6 .mu.m]; and [0048] each initial gloss value is
measured at a 20.degree. angle, one day (24 hours) after the film
has been cast.
[0049] As used herein PVC means a polyvinylchloride substrate used
as described in the test methods herein.
[0050] Dry film thickness is measured herein after 24 hours of
drying, under standard conditions. As used herein, unless the
context indicates otherwise, the terms `standard conditions`
denotes a relative humidity of 50%.+-.5%, ambient temperature and
an air flow less than or equal to 0.1 m/s; and `ambient
temperature` denotes 23.degree. C..+-.2.degree..
[0051] The telegraphing values herein will be positive numbers. In
general the greater the reduction in telegraphing, the smaller will
be the telegraphing value.
[0052] The term "comprising" as used herein means that the list
that immediately follows is non exhaustive and may or may not
include any other additional suitable items, for example one or
more further feature(s), component(s), ingredient(s) and/or
substituent(s) as appropriate. "Substantially comprising" as used
herein means a component or list of component(s) is present in a
given material in an amount greater than or equal to about 90%,
preferably .gtoreq.95%, more preferably .gtoreq.98% by weight of
the total amount of the given material. The term "consisting of" as
used herein mean that the list that follows is exhaustive and does
not include additional items.
[0053] For all upper and lower boundaries of any parameters given
herein, the boundary value is included in each range for each
parameter. All combinations of minimum and maximum values of the
parameters described herein may be used to define the parameter
ranges for various embodiments and preferences of the
invention.
[0054] It will be understood that the total sum of any quantities
expressed herein as percentages cannot (allowing for rounding
errors) exceed 100%. For example the sum of all components of which
the composition of the invention (or part(s) thereof) comprises
may, when expressed as a weight (or other) percentage of the
composition (or the same part(s) thereof), total 100% allowing for
rounding errors. However where a list of components is
non-exhaustive the sum of the percentage for each of such
components may be less than 100% to allow a certain percentage for
additional amount(s) of any additional component(s) that may not be
explicitly described herein.
[0055] As used herein the terms oligomer and polymer both refer to
macromolecules which comprises a plurality of units derived,
actually or conceptually, from molecules of lower molecular mass.
These terms may also be used adjectivally to describe a part or the
whole of a macromolecule. Often the term oligomer may be used more
specifically to refer to macromolecules of intermediate relative
molecular mass, where the oligomer properties vary significantly
with the removal of one or a few units. Polymer may be used both
generally to refer to any macromolecule and also more specifically
to refer to macromolecules of high relative molecular mass where
usually addition or removal of one or a few units has a negligible
effect on the molecular properties (although this may not be always
be the case for example where polymers have certain properties that
are critically dependent on fine details of the molecular
structure). It will be understood that the molecular mass boundary
between an oligomer and a polymer (in its specific rather than
general meaning) may vary according to the specific macromolecule
and/or applications of interest and so they may be significant
overlap where the same macromolecules may be considered both a
oligomer and a polymer. Therefore, unless the context herein
clearly indicates otherwise, the terms oligomer and polymer are
used herein interchangeably.
[0056] Preferably the coating compositions of the invention are
non-adhesive compositions. As used herein the term `non-adhesive
composition` denotes any composition that does not remain
substantially tacky after drying under ambient conditions for a
length of time which would be commercially acceptable. Non-adhesive
compositions may be those which have a tack-free time of less than
or equal to 16 hours, preferably .ltoreq.10 hours, more preferably
.ltoreq.6 hours, most preferably .ltoreq.4 hours. Tack free time
may conveniently be measured as described herein.
[0057] Preferably said autoxidisable vinyl polymer comprises fatty
acid residues in an amount from 41% to 75% by weight of said
autoxidisable vinyl polymer.
[0058] Preferably the at least one other ethylenically unsaturated
vinyl monomer in step (A) (ii) is other than styrene, a
(alpha)-methyl styrene, vinyl toluene and/or mixtures thereof. More
preferably the at least one other ethylenically unsaturated vinyl
monomer does not comprise any styrenic monomer(s), i.e. monomers
that comprise an optionally substituted vinyl benzene moiety.
[0059] Compositions of the invention may be aqueous (comprising
aqueous solutions and/or emulsions where the continuous phase is
aqueous) or be solvent-based (comprising a solvent other than water
such as organic solvent).
[0060] Preferably where said composition is aqueous, said aqueous
composition has a co-solvent content less that 25% by total weight
of said composition.
[0061] Another aspect of the present invention provides a process
for obtaining an autoxidisable vinyl polymer where:
said autoxidisable vinyl polymer is capable of forming a coating
composition which when in the form of the film has a telegraphing
value of less than 10 gloss units (as defined herein); the process
comprising the steps of: [0062] I) polymerising ethylenically
unsaturated vinyl monomers comprising: [0063] i) at least one epoxy
functional vinyl monomer in an amount from 15% to 100% by weight of
the total monomers in step I); and [0064] ii) at least one other
ethylenically unsaturated vinyl monomer in an amount from 0% to 85%
by weight of the total monomers in step I); [0065] to obtain an
epoxy functional vinyl polymer; and [0066] II) reacting said epoxy
functional vinyl polymer obtained in step I) with fatty acids
having an average iodine value from 30 to 250 g I.sub.2/100 g fatty
acid; [0067] where the resultant autoxidisable vinyl polymer has
[0068] i) a vinyl polymer backbone in an amount from 25% to 75% by
weight of said autoxidisable vinyl polymer; [0069] ii) fatty acid
residue in an amount from 25% to 75% by weight of said
autoxidisable vinyl polymer; [0070] iii) a T.sub.g from -60.degree.
C. to +20.degree. C., [0071] iv) a weight average molecular weight
(M.sub.w) from 3,500 to 50,000 g/mol; and [0072] v) a PDi from 2 to
10.
[0073] Preferably in one embodiment of the invention said resultant
autoxidisable vinyl polymer comprises a vinyl polymer backbone in
an amount from 25% to 72%, more preferably 25% to 63% most
preferably 25% to 59% by weight of said autoxidisable vinyl
polymer. Conveniently where said composition is solvent-based, said
autoxidisable vinyl group polymer comprises a vinyl polymer
backbone in an amount from 25% to 55% by weight of said
autoxidisable polymer.
[0074] Preferably in another embodiment of the invention said
resultant autoxidisable vinyl polymer comprises fatty acid residues
in an amount from 28% to 75%, more preferably 37% to 75%, most
preferably 41% to 75% by weight of said autoxidisable vinyl
polymer.
[0075] Preferably the at least one other ethylenically unsaturated
vinyl monomer in step I) (ii) is other than styrene, a
(alpha)-methyl styrene, vinyl toluene and/or mixtures thereof. More
preferably the at least one other ethylenically unsaturated vinyl
monomer does not comprise any styrenic monomer(s).
[0076] Preferably the composition of the invention is substantially
free of cationic quaternary ammonium species.
[0077] Preferably said epoxy functional vinyl polymer (prepared
before fatty acid functionalisation as described herein) has a
number average molecular weight (M.sub.n) from 1500 to 10000 g/mol,
more preferably 1600 to 5000 g/mol and most preferably 1700 to 4000
g/mol.
[0078] Preferably at least 70% of all epoxide groups present in the
epoxy functional polymers obtained as described herein react with a
fatty acid.
[0079] Preferred compositions of the invention produce coatings
that have a telegraphing value (as defined herein) of less than 7
gloss units, more preferably less than 4 gloss units and most
preferably less than 2 gloss units.
[0080] Preferably the initial rough gloss should not deteriorate
significantly over time. This can be measured as a `gloss decay`
defined as the initial rough gloss minus a rough gloss measured at
a later specified time. For example "gloss decay (`n` days)" is
calculated as the initial rough gloss (measured 1 day after film
formation) minus the rough gloss measured `n` days after film
formation (i.e. in this case n is always >1). Preferably the
gloss decay is measured 4 days, more preferably 7 days and most
preferably 14 days after film formation. Preferred values of gloss
decay (for example after each of the periods given above) are less
than 14 gloss units, more preferably less than 10 gloss units, most
preferably less than 7 gloss units and especially less than 4 gloss
units.
[0081] Without wishing to be bound by any theory it is believed
that the vinyl polymers of the invention have a comb like structure
allowing excellent control of molecular weight distribution to give
a relatively narrow distribution resulting in good flow, reduced
telegraphing and fast drying. In contrast conventional vinyl
polymers are typically highly branched and are typically used close
to their gel point. The vinyl polymers of the invention are also
more hydrolytically stable and their backbone is more resistant to
hydrolysis. These properties are especially important for
decorative paints which may stay on the shelf for a long time.
[0082] Polymers of the invention have a narrow molecular weight
distribution (PDi) and a relatively low weight average molecular
weight (M.sub.w) and therefore an improved balance between M.sub.w
and PDi. As such polymers have less material of low molecular
weight, coating compositions of the invention (comprising such
polymers) can dry fast, for example have short dust and/or tack
free times. Compositions of the invention have other advantages.
They may be prepared with lower viscosities due to the reduced
amount of high molecular weight material. For example in solvent
borne systems less solvent is needed to achieve a certain viscosity
and in aqueous systems lower viscosity can reduce telegraphing.
Alternatively compositions with a similar solvent content to the
prior art can be produced with a higher overall molecular weight.
Compositions of the invention can also be prepared with a high
solids content.
[0083] The M.sub.p is the molecular weight with the highest signal
(i.e. the apex of the peak) in a chromatogram resulting from the
measuring of the molecular weight of the invention composition
using Gel Permeation Chromatography (GPC). The M.sub.p is also
known as the peak M.sub.w. M.sub.p values are discussed in Modern
Size Exclusion Liquid Chromatography, W. W. Yau, J. K. Kirkland and
D. D. Bly, John Wiley & Sons, USA, 1997.
[0084] Compositions of the invention may also comprise one or more
autoxidisable reactive diluents, where the diluent(s) have one or
more of the following properties: [0085] I) a M.sub.p from 1700 to
4000 g/mol; [0086] II) a PDi from 1 to 2; and/or [0087] III) an oil
length .gtoreq.50%.
[0088] The reactive diluents may be present in the compositions of
the invention in an amount from 0% to 50%, more preferably from 5%
to 50%, by weight of the autoxidisable vinyl polymer.
[0089] As used herein the term `oil length` denotes the percentage
of oil (i.e. liquid miscible in an organic solvent) in a resin or
polymer by weight of the resin or polymer and may be measured by
any conventional method well known to those in the art.
[0090] Preferred reactive diluents (which may or may not be the
autoxidisable and/or have the properties given above) may also have
one or more of the following properties:
M.sub.n>1000 g/mol, more preferably >1500 g/mol and most
preferably >2000 g/mol; M.sub.n<5000 g/mol, more preferably
<4000 g/mol and especially <3500 g/mol; and/or optionally
(e.g. where the reactive diluent is autoxidisable) from 60 to 90 wt
%, more preferably 75 to 90%, most preferably 80 to 90% of fatty
acid residues with an iodine value from 50 to 175, more preferably
from 80 to 150 g I.sub.2/100 g by weight of sample.
[0091] Preferably the autoxidisable vinyl polymer will cross-link
at ambient temperature. Cross-linking by autoxidation means the
cross-linking results from an oxidation occurring in the presence
of air, usually involving a free radical mechanism and is
preferably metal-catalysed resulting in covalent bonds. Suitable
autoxidation is provided by for example fatty acid residues
comprising unsaturated bonds, allyl functional residues and/or
.beta.(beta)-keto ester groups, preferably by fatty acid residues
comprising unsaturated bonds.
[0092] As used herein `fatty acid residue` (or FA residue), means
fatty acids, simple derivatives thereof (such as esters (e.g.
C.sub.1-4alkyl esters), salts, soaps, oils, fats and/or waxes) and
mixtures thereof. As used herein `fatty acid` means any
predominately unbranched, non-cyclic (preferably substantially
linear) aliphatic carboxylic acid that substantially comprises,
preferably consists of an aliphatic hydrocarbon chain and at least
one carboxy group, preferably a single terminal carboxyl group
(i.e. located at the end of the chain). Fatty acids may comprise a
limited number of other substituents such as hydroxyl and may be
saturated, mono-unsaturated or poly-unsaturated.
[0093] The fatty acid residue may be obtained from one or more
natural and/or artificial source. Natural sources include animal
sources and/or plant sources. Animal sources may comprise animal
fat, butter fat, fish oil, lard, liver fats, sperm whale oil and/or
tallow oil and waxes. Examples of waxes are beeswax, candelia
and/or montan. Plant sources may comprise waxes and/or oils such as
vegetable oils and/or non-vegetable oils. Examples of plant oils
are: bitter gourd, borage, calendula, canola, castor, china wood,
coconut, conifer seed, corn, cottonseed, dehydrated castor,
flaxseed, grape seed, Jacaranda mimosifolia seed, linseed, olive,
palm, palm kernel, peanut, pomegranate seed, rapeseed, safflower,
snake gourd, soya(bean), sunflower, tung, and/or wheat germ.
Artificial sources include synthetic waxes (such as micro
crystalline and/or paraffin wax), distilling tall oil (a by-product
of processing pine wood) and/or synthesis (for example by chemical
and/or biochemical methods). Fatty acid residues having conjugated
double bonds may be obtained by catalytic isomerisation of natural
fatty acids and/or dehydrated castor oil. Conjugated oils are
preferably obtained by dehydration of castor oil. Fatty acid
residues may be obtained and/or obtainable from a plurality of the
above sources and/or other sources not listed herein.
[0094] Preferred fatty acid residues may comprise fatty acid(s)
having from 4 to 36, more preferably from 8 to 26, most preferably
from 10 to 24, especially 12 to 22 carbon atoms. Generally fatty
acids obtained from natural sources have an even number of carbon
atoms due to their method of bio-synthesis, however fatty acids
with an odd number of carbon atoms may also be useful in the
present invention. Fatty acid residues may comprise fatty acids
with one or more carboxylic acid groups, for example dimer or
trimer fatty acids. Preferred fatty acids are mono functional, more
preferably C.sub.10-24 mono functional carboxylic acids, most
preferably C.sub.12-22 linear mono functional terminal carboxy
acids.
[0095] As long as oxidative drying of the polymer is not impaired
the fatty acid residue may comprise one or more saturated fatty
acids and/or oils, however at least some unsaturated fatty acid(s)
is needed for auto-oxidation to occur. In general the more
unsaturation present the more rapid the autoxidiative drying.
[0096] An iodine number may be used to indicate the amount of
unsaturation contained in fatty acids where a higher the iodine
number indicates more unsaturated double bonds are present.
Preferably the fatty acid residue used herein has an average iodine
value greater than or equal to 50, more preferably .gtoreq.80 and
most preferably .gtoreq.100 g I.sub.2/100 g fatty acid. Preferably
the fatty acid residue used herein has an average iodine value less
than or equal to 200, more preferably .ltoreq.180 and most
preferably .ltoreq.150 g I.sub.2/100 g fatty acid. The iodine value
may be measured conventionally or preferably as described in the
test methods herein.
[0097] For the purpose of determining the amount of fatty acid
residue used to obtain the vinyl polymer of the invention, it is
convenient to calculate the weight of the fatty acid reactant by
including the carbonyl group, but excluding the hydroxyl group of
the terminal acid group of the fatty acid molecule.
[0098] Preferably the minimum amount of fatty acid residues in the
autoxidisable vinyl polymer is greater than or equal to 35%, more
preferably .gtoreq.40% and most preferably .gtoreq.45% and
especially .gtoreq.48% by weight of the polymer.
[0099] Preferably the maximum amount of fatty acid residue in the
autoxidisable vinyl polymer is less than or equal to 68%, more
preferably .ltoreq.62%, most preferably .ltoreq.58% by weight of
the polymer.
[0100] Preferably the fatty acid residue comprises C.sub.10-30
fatty acids, more preferably C.sub.16-20 fatty acids, in an amount
greater than or equal to 80% by weight of the fatty acid residue.
More preferably the fatty acid residue substantially comprises,
most preferably consists of C.sub.10-30 fatty acids, especially
C.sub.16-20 fatty acids.
[0101] If the fatty acid residue comprises saturated fatty acids
they may be present in an amount less than or equal to 50%, more
preferably .ltoreq.20% and most preferably from 3% to 18% by weight
of the fatty acid residue.
[0102] Preferred vinyl polymers are those in which the
autoxidisable groups are mainly derived from fatty acid residue.
More preferably the fatty acid residue mainly comprises, most
preferably substantially comprises unsaturated fatty acids. Useful
unsaturated fatty acids have two or more double bonds and more
usefully are conjugated fatty acids.
[0103] Preferably at least 40% by weight, more preferably at least
60% by weight of the unsaturated fatty acids in the fatty acid
residue are fatty acids that contain at least two ethylenically
unsaturated groups (i.e. are polyunsaturated).
[0104] Preferred fatty acid residues comprise at least one
conjugated fatty acid. The total amount of conjugated fatty acid
may be greater than 0%, preferably .gtoreq.10% by weight of the
unsaturated fatty acid. The total amount of conjugated fatty acid
may be less than or equal to 70%, preferably .ltoreq.55%, more
preferably .ltoreq.40%, by weight of the unsaturated fatty acid.
The autoxidisable vinyl polymer may be obtained from a mixture of
conjugated and non-conjugated unsaturated fatty acids.
[0105] A known problem with many autoxidisable coating compositions
is that the resultant coatings have a tendency to yellow, in
particular where the autoxidisable groups are derived from
polyunsaturated fatty acids (e.g. those described herein). This may
be unacceptable depending on the desired color of the resultant
coating.
[0106] Therefore in another embodiment of the invention to reduce
yellowing, preferred autoxidisable vinyl polymers are those where
the unsaturated fatty residue comprises low amounts of highly
polyunsaturated fatty acids. For example vinyl polymers that are
more resistant to yellowing may be obtained and/or obtainable from
fatty acid residue that comprise by weight of total fatty acid less
than or equal to 10%, more preferably .ltoreq.7%, most preferably
.ltoreq.4% and especially .ltoreq.2% of fatty acids with three or
more double bonds. Examples of fatty acids that include three or
more double bonds are given herein.
[0107] Preferred compositions of the invention have an initial
yellowness value of less than or equal to 10, more preferably
.ltoreq.7 and most preferably .ltoreq.4, when measured using the
test method described herein. Preferred compositions show only a
small increase in yellowness (.DELTA.b value) after being held in
darkness for 3 weeks at 52.degree. C., more preferably .DELTA.b is
less than or equal to 10, still more preferably is .ltoreq.7, most
preferably .ltoreq.5 and especially .ltoreq.3.
[0108] In yet another embodiment of the invention (e.g. where
yellowing is not a concern) preferred autoxidisable vinyl polymers
are those where the unsaturated fatty residue comprises higher
amounts of highly polyunsaturated fatty acids (such as fatty acids
with three or more double bonds) as this can improve the speed of
autoxidative drying.
[0109] Preferably the unsaturated fatty acid is covalently bound to
the vinyl polymer in a one step process, either though the use of a
fatty acid functional vinyl monomer or through a reaction of the
fatty acid with the vinyl polymer.
[0110] It is preferred that glycidyl esters of unsaturated fatty
acids are not used in the preparation of the autoxidisable vinyl
polymer as the synthesis of these glycidyl esters requires toxic
raw materials like for instance epichlorohydrine which will also
give chlorine containing waste material which is undesirable. A
glycidyl ester of an unsaturated fatty acid is an epoxy functional
fatty acid material (usually with a number average molecular weight
(M.sub.n) below 400) where the acid group has been reacted to
obtain a glycidyl end group.
[0111] Optionally the fatty acid residue may also comprise one or
more alkynyl group(s) and/or one or more (non carboxy) hydroxyl
group(s).
[0112] Non limiting examples of some common fatty acids that may be
used in the present invention are listed below as their systematic
(IUPAC) names with their trivial name(s) in square parentheses
where known. It will be appreciated that in practice most fatty
acid residues (especially those obtained from natural sources) will
comprise a mixture of many of these acids as well as other acids
not specifically listed herein.
[0113] Saturated fatty acids may be selected from: [0114] butanoic
[butyric] acid (C.sub.4H.sub.8O.sub.2), pentanoic [valeric] acid
(C.sub.5H.sub.10O.sub.2), hexanoic [caproic] acid
(C.sub.6H.sub.12O.sub.2), heptanoic [enanthic] acid
(C.sub.7H.sub.14O.sub.2), octanoic [caprylic] acid
(C.sub.8H.sub.16O.sub.2), nonanoic [pelargonic] acid
(C.sub.9H.sub.18O.sub.2), decanoic [capric] acid
(C.sub.10H.sub.20O.sub.2), dodecanoic [lauric] acid
(C.sub.12H.sub.24O.sub.2), tetradecanoic [myristic] acid
(C.sub.14H.sub.28O.sub.2), hexadecanoic [palmitic] acid
(C.sub.16H.sub.32O.sub.2), heptadecanoic [margaric also daturic]
acid (C.sub.17H.sub.34O.sub.2), octadecanoic [stearic] acid
(C.sub.18H.sub.36O.sub.2), eicosanoic [arachidic] acid
(C.sub.20H.sub.40O.sub.2), docosanoic [behenic] acid
(C.sub.22H.sub.44O.sub.2), tetracosanoic [lignoceric] acid
(C.sub.24H.sub.48O.sub.2), hexacosanoic [cerotic] acid
(C.sub.26H.sub.52O.sub.2), heptacosanoic [carboceric] acid
(C.sub.27H.sub.54O.sub.2), octacosanoic [montanic] acid
(C.sub.28H.sub.56O.sub.2), triacontanoic [melissic] acid
(C.sub.30H.sub.60O.sub.2), dotriacontanoic [lacceroic] acid
(C.sub.32H.sub.64O.sub.2), tritriacontanoic [ceromelissic also
psyllic] acid (C.sub.33H.sub.66O.sub.2), tetratriacontanoic
[geddic] acid (C.sub.34H.sub.68O.sub.2) and/or pentatriacontanoic
[ceroplastic] acid (C.sub.35H.sub.70O.sub.2).
[0115] Mono-unsaturated fatty acids may be selected from: [0116]
(Z)-decan-4-enoic [obtusilic] acid (C.sub.10H.sub.18O.sub.2),
(Z)-decan-9-enoic [caproleic] acid (C.sub.10H.sub.18O.sub.2),
(Z)-undecan-10-enoic [undecylenic also 10-hendecenoic] acid
(C.sub.11H.sub.20O.sub.2), [0117] (Z)-dodan-4-ecenoic [linderic]
acid (C.sub.12H.sub.22O.sub.2), (Z)-dodecan-5-enoic (lauroleic)
acid (C.sub.12H.sub.22O.sub.2), (Z)-tetradecan-4-enoic [tsuzuic]
acid (C.sub.14H.sub.26O.sub.2), (Z)-tetradecan-5-enoic [physeteric]
acid (C.sub.14H.sub.26O.sub.2), (Z)-tetradecan-9-enoic
[myristoleic] acid (C.sub.14H.sub.26O.sub.2), [0118]
(Z)-hexadan-6-enoic [sapienic] acid (C.sub.16H.sub.30O.sub.2),
(Z)-hexadan-9-enoic [palmitoleic] acid (C.sub.16H.sub.30O.sub.2),
(Z)-octadecan-6-enoic [petroselinic] acid
(C.sub.18H.sub.34O.sub.2), (E)-octadecan-9-enoic [elaidic] acid
(C.sub.18H.sub.34O.sub.2), (Z)-octadecan-9-enoic [oleic] acid
(C.sub.18H.sub.34O.sub.2), [0119] (Z)-octadecan-11-enoic [vaccenic
also asclepic] acid (C.sub.18H.sub.34O.sub.2), (Z)-eicosan-9-enoic
[gadoleic] acid (C.sub.20H.sub.38O.sub.2), (Z)-eicosan-11-enoic
[gondoic] acid (C.sub.20H.sub.38O.sub.2), [0120]
(Z)-docosan-11-enoic [cetoleic] acid (C.sub.22H.sub.42O.sub.2),
(Z)-docosan-13-enoic [erucic] acid (C.sub.22H.sub.42O.sub.2) and/or
(Z)-tetracosan-15-enoic [nervonic] acid
(C.sub.24H.sub.46O.sub.2).
[0121] Di-unsaturated fatty acids may be selected from: [0122]
(5Z,9Z)-hexadeca-5,9-dienoic acid (C.sub.16H.sub.28O.sub.2), [0123]
(5Z,9Z)-octadeca-5,9-dienoic [taxoleic] acid
(C.sub.18H.sub.32O.sub.2), [0124] (9Z,12Z)-octadeca-9,12-dienoic
[linoleic] acid (C.sub.18H.sub.32O.sub.2), [0125]
(9Z,15Z)-octadeca-9,15-dienoic acid (C.sub.18H.sub.32O.sub.2)
and/or [0126] (7Z,11Z)-eicosa-7,11-dienoic [dihomotaxoleic] acid
(C.sub.20H.sub.36O.sub.2).
[0127] Tri-unsaturated fatty acids may be selected from: [0128]
(5Z,9Z,12Z)-heptadeca-5,9,12-trienoic acid
(C.sub.17H.sub.28O.sub.2), [0129]
(3Z,9Z,12Z)-octadeca-3,9,12-trienoic acid
(C.sub.18H.sub.30O.sub.2), [0130]
(5Z,9Z,12Z)-octadeca-5,9,12-trienoic [pinolenic] acid
(C.sub.18H.sub.30O.sub.2), [0131]
(6Z,9Z,12Z)-octadeca-6,9,12-trienoic acid [.gamma.(gamma)-linolenic
acid also GLA] (C.sub.18H.sub.30O.sub.2),
(8E,10E,12Z)-octadeca-8,10,12-trienoic [calendic] acid
(C.sub.18H.sub.30O.sub.2), [0132]
(8Z,10E,12Z)-octadeca-8,10,12-trienoic [jacaric] acid
(C.sub.18H.sub.30O.sub.2), [0133]
(9E,11E,13E)-octadeca-9,11,13-trienoic [.beta.(beta)-eleostearic
also .beta.-oleostearic] acid (C.sub.18H.sub.30O.sub.2),
(9E,11E,13Z)-octadeca-9,11,13-trienoic [catalpic] acid
(C.sub.18H.sub.30O.sub.2), [0134]
(9Z,11E,13E)-octadeca-9,11,13-trienoic [.alpha.(alpha)-eleostearic
also .alpha.-oleostearic] acid (C.sub.18H.sub.30O.sub.2) (where
.alpha.-eleostearic acid comprises >65% of the fatty acids of
tung oil), [0135] (9Z,11E,13Z)-octadeca-9,11,13-trienoic [punicic
also trichosanic] acid (C.sub.18H.sub.30O.sub.2), [0136]
(9Z,11E,15Z)-octadeca-9,11,13-trienoic [rumelenic] acid
(C.sub.18H.sub.30O.sub.2), [0137]
(9Z,13E,15Z)-octadeca-9,13,13-trienoic acid
(C.sub.18H.sub.30O.sub.2), [0138]
(9Z,12Z,15Z)-octadeca-9,12,15-trienoic acid
[.alpha.(alpha)-linolenic acid also ALA] (C.sub.18H.sub.30O.sub.2),
(5Z,8Z,11Z)-eicosa-5,8,11-trienoic
[dihomo-.gamma.(gamma)-linolenic] acid (C.sub.20H.sub.34O.sub.2),
(5Z,11Z,14Z)-eicosa-8,11,14-trienoic [sciadonic] acid
(C.sub.20H.sub.34O.sub.2) and/or [0139]
(8Z,11Z,14Z)-eicosa-8,11,14-trienoic [Mead] acid
(C.sub.20H.sub.34O.sub.2).
[0140] Tetra-unsaturated fatty acids may be selected from: [0141]
(6Z,8Z,10Z,12Z)-hexadeca-6,8,10,15-tetraenoic acid
(C.sub.16H.sub.24O.sub.2), [0142]
(6Z,8Z,10Z,12Z)-octadeca-6,8,10,12-tetraenoic acid
(C.sub.18H.sub.28O.sub.2), [0143]
(6Z,9Z,12Z,15Z)-octadeca-6,9,12,15-tetraenoic [stearidonic] acid
(C.sub.18H.sub.28O.sub.2), [0144]
(9Z,11E,13E,15Z)-octadeca-9,11,13,15-tetraenoic
[.alpha.(alpha)-parinaric] acid (C.sub.18H.sub.28O.sub.2), [0145]
(9Z,11Z,13Z,15Z)-octadeca-9,11,13,15-tetraenoic
[.beta.(beta)-parinaric] acid (C.sub.18H.sub.28O.sub.2), [0146]
(5Z,8Z,11Z,14Z)-eicosa-5,8,11,14-tetraenoic acid [arachidonic acid
also AA] (C.sub.20H.sub.32O.sub.2),
(6Z,8Z,10Z,12Z)-eicosa-6,8,10,12-tetraenoic acid
(C.sub.20H.sub.32O.sub.2), [0147]
(8Z,11Z,14Z,11Z)-eicosa-8,11,14,17-tetraenoic acid
(C.sub.20H.sub.32O.sub.2), [0148]
(6Z,8Z,10Z,12Z)-docosa-6,8,10,12-tetraenoic acid
(C.sub.22H.sub.36O.sub.2) and/or [0149]
(7Z,10Z,13Z,16Z)-docosa-7,10,13,16-tetraenoic acid
(C.sub.22H.sub.36O.sub.2).
[0150] Penta-unsaturated fatty acids may be selected from: [0151]
(x,6Z,8Z,10Z,12Z)-hexadeca-x,6,8,10,12-pentaenoic acid(s)
(C.sub.16H.sub.22O.sub.2) where x denotes a fifth double bond
optionally in a position which does not conjugate with the other
four conjugated ethylenic double bonds, [0152]
(x',6Z,8Z,10Z,12Z)-eicosa-x',6,8,10,12-pentaenoic acid(s)
(C.sub.20H.sub.30O.sub.2) where x' denotes a fifth double bond
optionally in a position which does not conjugate with the other
four ethylenic double bonds, [0153]
(5E,7E,9E,14Z,17Z)-eicosa-5,8,11,14,17-pentaenoic acid
(C.sub.20H.sub.30O.sub.2), [0154]
(5Z,7E,9E,14Z,17Z)-eicosa-5,8,11,14,17-pentaenoic acid
(C.sub.20H.sub.30O.sub.2), [0155]
(5Z,8Z,11Z,14Z,17Z)-eicosa-5,8,11,14,17-pentaenoic acid [EPA]
(C.sub.20H.sub.30O.sub.2), [0156]
(7Z,10Z,13Z,16Z,19Z)-docosa-7,10,13,16,19-pentaenoic [clupanodonic]
acid (C.sub.22H.sub.34O.sub.2),
(4Z,7Z,10Z,13Z,16Z)-docosa-4,7,10,13,16-pentaenoic [osbond] acid
(C.sub.22H.sub.34O.sub.2) and/or
(7Z,10Z,13Z,16Z,19Z)-docosa-7,10,13,16,19-pentaenoic acid [DPA]
(C.sub.22H.sub.34O.sub.2).
[0157] Hexa-unsaturated fatty acids may be selected from: [0158]
(x'',y'',6Z,8Z,10Z,12Z)-eicosa-x'',y'',6,8,10,12-hexaenoic acid(s)
(C.sub.20H.sub.28O.sub.2) where x'' and y'' denote fifth and sixth
double bonds optionally in positions which do not conjugate with
the other four conjugated ethylenic double bonds, [0159]
(4Z,7Z,10Z,13Z,16Z,19Z)-docosa-4,7,10,13,16,19-hexaenoic acid [DHA]
(C.sub.22H.sub.32O.sub.2) and/or
(6Z,9Z,12Z,15Z,18Z,21Z)-tetracosa-6,9,12,15,18,21-hexaenoic
[nisinic] acid (C.sub.24H.sub.36O.sub.2).
[0160] Hepta-unsaturated fatty acids may be selected from: [0161]
(w''',x''',y''',6Z,8Z,10Z,12Z)-eicosa-w''',x''',y''',6,8,10,12-heptaenoic
acid(s) (C.sub.22H.sub.30O.sub.2) where x''' and y''' denote fifth,
sixth and seven double bonds optionally in positions which do not
conjugate with the other four conjugated ethylenic double bonds,
and/or [0162]
(4Z,7Z,9Z,11Z,13Z,16Z,19Z)-docosa-4,7,9,11,13,16,19-heptaenoic
[stellaheptaenoic] acid (C.sub.22H.sub.30O.sub.2).
[0163] Alkynyl-functional fatty acids may be selected from: [0164]
(9Z)-octadeca-9-en-12-ynoic [crepenynic] acid
(C.sub.18H.sub.30O.sub.2).
[0165] Hydroxy-functional fatty acids may be selected from: [0166]
12-hydroxy-(9Z)-octadeca-9-enoic [ricinoleic] acid
(C.sub.18H.sub.34O.sub.3).
[0167] The cross-linking of the vinyl polymer herein is by
autoxidation. In a preferred embodiment, metal ion cross-linking is
used in combination to the autoxidation mechanism, e.g. by use of
coordinative driers as is well known by those skilled in the art.
Optionally (although less preferred) autoxidation is used in
combination with other cross-linking mechanisms as are known in the
art. Other cross-linking mechanisms known in the art include the
reaction of alkoxysilane functional groups, Schiff base
cross-linking, epoxy groups reacting with amino, carboxylic acid or
mercapto groups, the reaction of amine or mercapto groups with
ethylenically unsaturated groups such as fumarate and acryloyl
groups, the reaction of masked epoxy groups with amino or mercapto
groups, the reaction of isothiocyanates with amines, alcohols or
hydrazines, the reaction of amines (for example ethylene diamine or
multifunctional amine terminated polyalkylene oxides) with
.beta.(beta)-diketo (for example acetoacetoxy or acetoamide) groups
to form enamines.
[0168] The drying process of a coating composition can be divided
into stages for example the period of time necessary to achieve
dust-free and/or tack-free, coatings using the tests described
herein.
[0169] Preferably the dust-free time is less than or equal to 4
hours, more preferably .ltoreq.2 hours and most preferably
.ltoreq.1 hour.
[0170] Preferably the tack-free time is less than or equal to 10
hours, more preferably .ltoreq.6 hours and most preferably
.ltoreq.4 hours and particularly preferred <3 hours.
[0171] A problem often encountered in waterborne autoxidisable
vinyl polymers is they have poor hydrolytic stability. This is a
particular problem when polymer bound carboxylic acid groups are
introduced by reaction with anhydrides, especially when in
neutralized form. This problem can be reduced significantly by
reducing the degree of water solubility of the autoxidisable resin.
However in practice a balance between hydrolytic stability and
water solubility is required.
[0172] The autoxidisable vinyl polymer may contain bound
hydrophilic water-dispersing groups. Suitable hydrophilic groups
are well known in the art, and can be ionic water-dispersing groups
or non-ionic water-dispersing groups. Preferred non-ionic
water-dispersing groups are polyalkylene oxide groups, more
preferably polyethylene oxide groups. A small segment of the
polyethylene oxide group can be replaced by a propylene oxide
segment and/or butylene oxide segment, however the polyethylene
oxide group should still contain ethylene oxide (EO) as a major
component. When the water-dispersible group is polyethylene oxide,
the preferred EO chain length is .gtoreq.4, more preferably
.gtoreq.8 and most preferably .gtoreq.15 EO units. Preferably if
the autoxidisable vinyl polymer contains polyalkylene oxide groups,
the vinyl polymer has a polyalkylene oxide (optionally EO) content
which is at least .gtoreq.0%, more preferably .gtoreq.2%, most
preferably .gtoreq.3.5% and especially .gtoreq.5% and/or is no more
than .ltoreq.50%, more preferably .ltoreq.30%, most preferably
.ltoreq.15% and especially .ltoreq.9% by weight of the
autoxidisable vinyl polymer. Preferably the polyalkylene oxide
(optionally EO) group has a M.sub.w from 175 to 5000 g/mol, more
preferably from 350 to 2200 g/mol, most preferably from 660 to 2200
g/mol.
[0173] Preferred ionic water-dispersing groups are anionic
water-dispersing groups, especially carboxylic, phosphate,
phosphonate or sulphonic acid groups. Most preferred are
carboxylic, phosphate or phosphonate groups. The anionic
water-dispersing groups are preferably fully or partially in the
form of a salt. Conversion to the salt form is optionally effected
by neutralisation of the autoxidisable vinyl polymer with a base,
preferably during the preparation of the autoxidisable vinyl
polymer and/or during the preparation of the composition of the
present invention. The anionic dispersing groups may in some cases
be provided by the use of a monomer having an already neutralised
acid group in the autoxidisable vinyl polymer synthesis so that
subsequent neutralisation is unnecessary. If anionic
water-dispersing groups are used in combination with a non-ionic
water-dispersing group, neutralisation may not be required.
[0174] If the anionic water-dispersing groups are neutralised, the
base used to neutralise the groups is preferably an amine or an
inorganic base. Suitable amines include tertiary amines, for
example triethyl amine or N,N-dimethyl ethanol amine. Suitable
inorganic bases include alkali hydroxides and carbonates, for
example lithium hydroxide, sodium hydroxide and/or potassium
hydroxide. Generally a base is used which gives the required
counter ion desired for the composition. For example, preferred
counter ions include tertiary amines or Li.sup.+, Na.sup.+,
K.sup.+.
[0175] Cationic water dispersible groups can also be used, but are
less preferred. Examples include pyridine groups, imidazole groups
and or quaternary ammonium groups which may be neutralised or
permanently ionised.
[0176] The autoxidisable vinyl polymer when in an aqueous coating
composition preferably has an acid value (AV, also referred to as
an acid number or AN) from 0 to 60, more preferably from 0 to 40,
most preferably from 0 to 12 and especially from 2 to 8 mg
KOH/g.
[0177] The autoxidisable vinyl polymer when in a solvent borne
coating composition preferably has an AV from 0 to 17, more
preferably from 2 to 10 mg KOH/g.
[0178] The autoxidisable polyvinyl polymer, if carboxylic acid
functional, preferably conforms to the following relationship
(where ND denotes the degree to which the acid groups of the
polymer are neutralised).
ND.times.AV.gtoreq.22, more preferably .gtoreq.27 and most
preferably .gtoreq.33 mg KOH/g. ND.times.AV.ltoreq.65, more
preferably .ltoreq.60 mg KOH/g.
[0179] ND is a dimensionless fraction from 0 to 1 that indicates of
the amount of neutralizing agent present in the polymer. For
example if 80% of the acid groups on the polymer are neutralised,
then the ND value is 0.8. AV is reported in units of mg KOH/g so
the product ND.times.AV has units of mg KOH/g. When the polymer is
not neutralised ND is 0 and so is ND.times.AV is also 0.
[0180] The autoxidisable vinyl polymer preferably has a hydroxyl
number which is at least .gtoreq.25, more preferably .gtoreq.48
and/or is no more than .ltoreq.135, more preferably .ltoreq.110 mg
KOH/g.
[0181] The aqueous coating composition of the invention preferably
has a pH which is at least .gtoreq.2.0, more preferably .gtoreq.3.4
and most preferably .gtoreq.5.1 and/or is no more than .ltoreq.9.2,
more preferably .ltoreq.8.4 and most preferably .ltoreq.7.6.
[0182] Preferably the weight average (M.sub.w) of the autoxidisable
vinyl polymer is at least .gtoreq.4000, more preferably
.gtoreq.5000, most preferably .gtoreq.7000 and/or is no more than
.ltoreq.40000 more preferably .ltoreq.35000, most preferably
.ltoreq.25000, especially .ltoreq.20000 and for example
.ltoreq.17000 g/mol. M.sub.w is measured by GPC using polystyrene
standards as described herein.
[0183] Preferably the majority of any cross-linking reaction only
takes place after application of the aqueous coating composition to
a substrate, to avoid an excessive molecular weight build up which
may lead to an increased viscosity of the aqueous coating
composition on the substrate in the early stages of drying.
[0184] The molecular weight distribution (MWD) of the autoxidisable
vinyl polymer has an influence on the viscosity of the vinyl
polymers in the composition and hence an influence on the
telegraphing. MWD is conventionally described by the polydispersity
index (PDi). PDi is defined as the weight average molecular weight
divided by the number average molecular weight (M.sub.w/M.sub.n)
and is dimensionless. It has been found that a lower PDi often
results in lower viscosity and improved flow for a polymer of given
M.sub.w. Preferably the autoxidisable vinyl polymer has a PDi which
is no more than .ltoreq.8.3, more preferably .ltoreq.7, most
preferably .ltoreq.5 and especially .ltoreq.4 and/or is at least
.gtoreq.2.5.
[0185] Preferably the weight average particle size of the
autoxidisable vinyl polymer (optionally when in an aqueous coating
composition) is at least .gtoreq.50 nm, more preferably .gtoreq.80
nm, most preferably .gtoreq.120 nm and especially .gtoreq.150 nm.
Preferably at least 80% of the particles have a weight average
particle size .ltoreq.1000 nm, more preferably .ltoreq.750 nm, most
preferably .ltoreq.550 nm and especially .ltoreq.400 nm.
[0186] Weight average particle size can be measured by any suitable
method such as that described in the test methods herein.
[0187] The glass transition temperature (T.sub.g) (as measured by
DSC of a solid material) of the autoxidisable vinyl polymer may
vary within a wide range and preferably is at least
.gtoreq.-60.degree. C., more preferably .gtoreq.-40.degree. C.,
more preferably .gtoreq.-25.degree. C. and/or preferably is no more
than .ltoreq.+20.degree. C., more preferably .ltoreq.+10.degree.
C., most preferably .ltoreq.-0.degree. C. and especially
.ltoreq.-5.degree. C. Conveniently the T.sub.g of the autoxidisable
vinyl polymer for use in aqueous coating compositions may be from
-15.degree. C. to 0.degree. C. and for solvent based coating
compositions may be from -45.degree. C. to -10.degree. C.
[0188] For use in an aqueous coating compositions, the T.sub.g of
the autoxidisable vinyl polymer backbone described herein is
preferably at least .gtoreq.0.degree. C., more preferably
.gtoreq.+10.degree. C., more preferably .gtoreq.+20.degree. C.
and/or is preferably no more than .ltoreq.+90.degree. C., more
preferably .ltoreq.+60.degree. C., most preferably
.ltoreq.+40.degree. C.
[0189] For use in solvent borne coating compositions, the T.sub.g
of the autoxidisable vinyl polymer backbone described herein is
preferably at least .gtoreq.-25.degree. C., more preferably
.gtoreq.-5.degree. C., more preferably .gtoreq.+10.degree. C.
and/or is preferably no more than .ltoreq.+60.degree. C., more
preferably .ltoreq.+45.degree. C., most preferably
.ltoreq.+40.degree. C.
[0190] If the T.sub.g can not be measured by DSC because the first
derivative of the DSC curve does not show any identifiable maximum,
an alternative method for determining the T.sub.g is by calculating
the T.sub.g using the following equation that relates viscosity of
the pure vinyl polymer to its T.sub.g (which is derived from the
Williams-Landau-Ferry [WLF] equation):
Ln(.eta.)=27.6-[40.2.times.(T-T.sub.9)]/[51.6+(T-T.sub.g)]
where: [0191] Ln(.eta.)=Natural logarithm of the viscosity of the
pure polymer expressed in Pas (measured at ambient temperature
using a shear rate from 0.005 to 1 s.sup.-1) [0192] T=23.degree.
C..+-.1.degree. C. (i.e. ambient temperature is used to measure the
viscosity of the pure polymer) and [0193] T.sub.g=glass temperature
expressed in .degree. C.
[0194] Functional groups (such as fatty acid residue or
water-dispersing groups) may be introduced into the autoxidisable
vinyl polymer using two general methods: i) by using monomers
carrying the functional group in the polymerisation process to form
autoxidisable polymer carrying the functional group; or ii) using
monomers bearing selected reactive groups where monomer is
subsequently reacted with a compound carrying the functional group
and also a reactive group of the type which will react with the
selected reactive groups on the monomer to provide attachment of
the functional group to the autoxidisable vinyl polymer via
covalent bonding. Thus the autoxidisable vinyl polymer may be
obtained by polymerising autoxidisable vinyl monomers with other
vinyl monomers, or, the autoxidisable groups may be attached to the
vinyl polymer after radical polymerisation of vinyl monomers to
make a vinyl polymer. Preferably the autoxidisable groups are
reacted with a vinyl polymer. More preferably the vinyl polymer
comprises epoxy functional groups most preferably
glycidyl(meth)acrylate monomers such as GMA.
[0195] The autoxidisable vinyl polymer may be prepared from GMA
optionally with other free radically polymerisable ethylenically
unsaturated monomer(s), and can comprise polymerised units of a
wide range of such monomers, especially those commonly used to make
binders for the coatings industry. By a vinyl polymer herein is
meant a homo- or co-polymer derived from addition polymerisation,
using a free radical initiated process which may be carried out in
an aqueous or non-aqueous medium, of one or more ethylenically
unsaturated monomers. Therefore by a vinyl monomer is meant an
ethylenically unsaturated monomer.
[0196] Examples of vinyl monomers which may be used to form the
vinyl polymer include but are not limited to 1,3-butadiene,
isoprene, styrene, .alpha.(alpha)-methyl styrene, divinyl benzene,
acrylonitrile, methacrylonitrile, vinyl ethers, vinyl esters such
as vinyl acetate, vinyl propionate, vinyl laurate, and vinyl esters
of versatic acid such as VeoVa 9 and VeoVa 10 (VeoVa is a trademark
of Shell), heterocyclic vinyl compounds, alkyl esters of
mono-ethylenically unsaturated dicarboxylic acids (such as
di-n-butyl maleate and di-n-butyl fumarate) and, in particular,
esters of acrylic acid and methacrylic acid of Formula 1:
CH.sub.2.dbd.CR.sup.1--COOR.sup.2 Formula I
where R.sup.1 is H or methyl and R.sup.2 is optionally substituted
C.sub.1-20 alkyl (preferably C.sub.1-8alkyl) or optionally
substituted C.sub.3-20 cycloalkyl (preferably C.sub.3-8
cycloalkyl), examples of which are methyl acrylate, methyl
methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate,
n-butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl
methacrylate, isopropyl acrylate, isopropyl methacrylate, n-propyl
acrylate, n-propyl methacrylate, and hydroxyalkyl (meth)acrylates
such as hydroxyethyl acrylate, hydroxyethyl methacrylate,
2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate,
4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate and their
modified analogues like Tone M-100 (Tone is a trademark of Union
Carbide Corporation).
[0197] Ethylenically unsaturated monocarboxylic, sulphonic and/or
dicarboxylic acids, such as acrylic acid, methacrylic acid,
.beta.-carboxy ethyl acrylate, fumaric acid and/or itaconic acid
may be used. Ethylenically unsaturated monomers such as
(meth)acrylamide and/or methoxypolyethyleneoxide (meth)acrylate may
also be used.
[0198] The vinyl monomer may optionally contain functional groups
to contribute to the cross-linking of the vinyl polymer(s) in the
coating. Examples of such groups include: maleic, epoxy, fumaric,
acetoacetoxy, .beta.(beta)-diketone, acryloyl, methacryloyl,
styrenic, (meth)allyl groups, mercapto groups, keto or aldehyde
groups (such as methyl vinyl ketone [MEK], diacetone acrylamide and
(meth)acrolein).
[0199] Preferred vinyl oligomers have a backbone made from a
monomer system comprising at least 40% of one or more monomers of
Formula I by weight of the oligomer. Such a preferred backbone for
the vinyl oligomer is defined herein as an (meth)acrylic oligomer.
A particularly preferred autoxidisable vinyl oligomer is an
autoxidisable acrylic oligomer (i.e. based predominantly on at
least one ester of acrylic and/or methacrylic acid). More
preferably, the monomer system for the vinyl backbone comprises at
least 50%, most preferably at least 60% of such monomers by weight
of oligomer. The other monomer(s) in such acrylic autoxidisable
vinyl oligomers (where used) may include one or more of the other
vinyl monomers mentioned above, and/or may include monomer(s)
different to such other monomers.
[0200] Particularly preferred monomers include butyl acrylate (all
isomers), butyl methacrylate (all isomers), methyl methacrylate,
ethyl hexyl methacrylate, esters of (meth)acrylic acid,
acrylonitrile, vinyl acetate.
[0201] Monomers useful for reacting the fatty acid with the vinyl
polymer to give fatty acid residues include epoxy functional vinyl
monomers like glycidyl (meth)acrylate (GMA) or
3,4-epoxy-cyclohexylmethyl-acrylate. Preferably a batch process is
used in a non-aqueous environment, defined as less than 10%, more
preferably less than 2%, most preferably 0% water by weight of the
total composition.
[0202] In a preferred embodiment 30 to 70 wt % of epoxy functional
monomer is used, before functionalisation to obtain an
autoxidisable vinyl polymer of the invention. Preferably the vinyl
polymer comprising epoxy functional monomer is then reacted with
fatty acid, where preferably between 0.4 and 0.95 equivalent of
fatty acid is reacted with the functional groups present on the
vinyl polymer. For this purpose, it is considered that a hydroxyl
functional group can react once with a fatty acid, whereas an epoxy
functional group can react twice, due to the additionally formed
hydroxyl group on ring opening. A particularly preferred epoxy
functional monomer is GMA.
[0203] The vinyl polymer backbone obtained in step I of the process
of the invention comprises preferably at least .gtoreq.15%, more
preferably .gtoreq.20%, most preferably .gtoreq.30% and especially
.gtoreq.35% and/or preferably no more than .ltoreq.100%, more
preferably .ltoreq.85%, still more preferably .ltoreq.80%, most
preferably .ltoreq.70% and especially .ltoreq.65% of an epoxy
functional vinyl monomer by weight of the vinyl polymer backbone.
The vinyl polymer backbone obtained in step I of the process of the
invention preferably comprises 35% to 60%, more preferably 40% to
55%, most preferably 47% to 53%, for example 50% of GMA by weight
of the vinyl polymer backbone.
[0204] Compared to HE(M)A based acrylates, GMA has the advantage of
maintaining a narrow PDi after functionalisation with fatty
acids.
[0205] Preferably the vinyl polymer prepared in step I (before
fatty acid functionalisation) contains .ltoreq.5%, more preferably
.ltoreq.2% and most preferably 0% of hydroxy functional monomers
(such as HEA and HEMA) by weight of the vinyl polymer prepared in
step I.
[0206] Preferably the vinyl polymer prepared in step I (before
fatty acid functionalisation) contains .ltoreq.40%, more preferably
.ltoreq.25% and most preferably .ltoreq.15% of styrenic monomers by
weight of the vinyl polymer prepared in step I.
[0207] Preferably the vinyl polymer prepared in step I (before
fatty acid functionalisation) is substantially free of chlorine
containing monomers. Substantially free means such monomers are in
an amount .ltoreq.1%, more preferably .ltoreq.0.5% and especially
0% by weight of the vinyl polymer prepared in step I.
[0208] Preferably the autoxidisable vinyl polymer obtained by the
process of the invention is substantially free of urethane groups
(--NH--C(.dbd.O)--O--) as the presence of such groups may result in
a higher molecular weight, broader molecular weight distribution,
higher viscosity, lower solid content and worse flow
properties.
[0209] The autoxidisable vinyl polymer is preferably prepared by
free radical polymerisation, although in some circumstances anionic
polymerisation may be used. The free radical polymerisation can be
performed by techniques known in the art, for example as emulsion
polymerisation, solution polymerisation, suspension polymerisation
or bulk polymerisation. For example the vinyl polymer may be
prepared in solvent/bulk, followed by dissipation in water, which
can be achieved by a) neutralizing acid groups, b) having already
neutralized acid groups (e.g. SO.sub.3Na), c) adding surfactant
and/or d) any combination of the above.
[0210] A free-radical polymerisation of vinyl monomer(s) to form a
cross-linkable vinyl autoxidisable vinyl polymer or precursor
autoxidisable vinyl polymer will require the use of a
free-radical-yielding initiator(s) to initiate the vinyl
polymerisation. Suitable free-radical-yielding initiators include
inorganic peroxides such as hydrogen peroxide, alkyl hydroperoxides
such as t-butyl hydroperoxide and cumene hydroperoxide; dialkyl
peroxides such as di-t-butyl peroxide and the like; and azo
initiators, like e.g. AIBN; mixtures may also be used. The peroxy
compounds are in some cases advantageously used in combination with
suitable reducing agents (redox systems) such as Na or K
pyrosulphite or bisulphite, and iso-ascorbic acid.
[0211] It may be desirable to control the molecular weight by
addition of a chain transfer agent to the free radical
polymerisation process. Conventional chain transfer agents may be
used such as mercaptans, sulphides, disulphides and halocarbons.
The technique known as catalytic chain transfer polymerisation
(CCTP) may be used to provide low molecular weights. In this case a
free radical polymerisation is carried out using a free radical
forming initiator and a catalytic amount of a selected transition
metal complex acting as a catalytic chain transfer agent (CCTA),
and in particular a selected cobalt chelate complex. Such a
technique has been described for example in N. S. Enikolopyan et
al, J. Polym. Chem. Ed., Vol 19, 879 (1981), U.S. Pat. No.
4,526,945, U.S. Pat. No. 4,680,354, EP-A-0196783, EP-A-0199436,
EP-A-0788518 and WO-A-87/03605.
[0212] The use of catalytic chain transfer agents provides four
important benefits. [0213] a) Very low concentrations of CCTA
(typically 1 to 1000 ppm by weight of vinyl monomer) are required
to attain the preferred low molecular weight polymer and thus the
polymers do not have the odor often associated with conventional
chain transfer agents. [0214] b) Vinyl autoxidisable vinyl polymer
prepared by CCTP contain a terminal unsaturated group on many, if
not every vinyl polymer molecule. This terminal unsaturation can
participate in autoxidation reactions for example in fatty acid
cross-linking systems. Thus cross-linkable vinyl autoxidisable
vinyl polymers of the present invention can have autoxidisable
cross-linker groups that comprise the unsaturated groups from fatty
acids as well as terminal unsaturated groups resulting from CCTP.
[0215] c) CCTP allows the preparation of a vinyl autoxidisable
vinyl polymer which has a narrower PDi than is achievable by the
use of conventional chain transfer agents for low M.sub.w
autoxidisable vinyl polymer. [0216] d) When epoxy functional
monomers are used, CCTP has the advantage that the CCTA does not
react with the epoxy groups, unlike other conventional chain
transfer agents (such as mercaptans) which do react with
epoxides.
[0217] The autoxidisable vinyl polymer may be dispersed in water
using techniques well known in the art. When the autoxidisable
vinyl polymer has a low acid value or low degree of neutralisation
an external surfactant is normally required to disperse the polymer
in water. Mixing at high shear can also be used to assist
dispersion. Suitable surfactants include but are not limited to
conventional anionic, cationic and/or non-ionic surfactants such as
Na, K and NH.sub.4 salts of dialkyl sulphosuccinates, Na, K and
NH.sub.4 salts of sulphated oils, Na, K and NH.sub.4 salts of alkyl
sulphonic acids, Na, K and NH.sub.4 alkyl sulphates, alkali metal
salts of sulphonic acids; fatty alcohols, ethoxylated fatty acids
and/or fatty amides, and Na, K and NH.sub.4 salts of fatty acids
such as Na stearate and Na oleate. Other anionic surfactants
include alkyl or (alk)aryl groups linked to sulphonic acid groups,
sulphuric acid half ester groups (linked in turn to polyglycol
ether groups), phosphonic acid groups, phosphoric acid analogues
and phosphates or carboxylic acid groups. Cationic surfactants
include alkyl or (alk)aryl groups linked to quaternary ammonium
salt groups. Non-ionic surfactants include polyglycol ether
compounds and polyethylene oxide compounds. The surfactants may
also be polymeric surfactants which are also described as wetting
agents.
[0218] The amount of total surfactants used in aqueous compositions
of the invention is preferably at least .gtoreq.0.1%, more
preferably .gtoreq.1%, most preferably .gtoreq.3 and/or is
preferably no more than .ltoreq.11%, more preferably .ltoreq.9% and
most preferably .ltoreq.7% by weight of the autoxidisable vinyl
polymer. Preferably a mixture of anionic and non-ionic surfactants
are used.
[0219] If the aqueous composition comprising anionic surfactant,
the anionic surfactant may comprise ethylene oxide (EO) groups in
an amount which is preferably no more than .ltoreq.90%, more
preferably .ltoreq.70%; most preferably .ltoreq.55% and/or is
preferably at least .gtoreq.10% and/or .gtoreq.20% EO groups by
weight of the surfactant. Preferred anionic surfactants comprise
sulphate, sulphonate, phosphate and/or phosphonate groups.
[0220] The aqueous composition may comprise non-ionic surfactant in
an amount of preferably at least .gtoreq.0.1%, more preferably
.gtoreq.0.5%, still more preferably .gtoreq.1% and most preferably
.gtoreq.1.5% and/or preferably no more than .ltoreq.12%, more
preferably .ltoreq.9%, still more preferably .ltoreq.5% and most
preferably .ltoreq.3.5% by weight of vinyl polymer solids.
[0221] Optionally to reduce the effect of cissing the composition
comprises ionic surfactant in an amount of at least preferably
.gtoreq.0.1%, more preferably .gtoreq.0.5%, still more preferably
.gtoreq.1% and most preferably .gtoreq.1.5% and/or no more than
preferably .ltoreq.12%, more preferably .ltoreq.9%, most preferably
.ltoreq.5% by weight of vinyl polymer solids.
[0222] Dispersants (such as dispersing compounds and/or dispersing
resin) which preferably are autoxidisable (such as W-3000 available
from Perstorp or as described in EP1870442) could also be employed
instead of or combined with more conventional surfactants.
Optionally where used the dispersant (such as a dispersing resin)
is present in amount of at least preferably .gtoreq.0.1%, more
preferably .gtoreq.3% and most preferably .gtoreq.5% and/or no more
than preferably .ltoreq.30%, more preferably .ltoreq.20% and most
preferably .ltoreq.12% by weight of solid resin.
[0223] The solids content of aqueous coating compositions of the
invention may be at least preferably .gtoreq.33%, more preferably
.gtoreq.38%, most preferably .gtoreq.42% and especially .gtoreq.49%
and/or may be no more than preferably .ltoreq.72%, more preferably
<65% and most preferably .ltoreq.63% by total weight of the
composition.
[0224] The solids content of solvent-based coating compositions of
the invention is preferably .gtoreq.65%, more preferably
.gtoreq.70%, most preferably .gtoreq.75% and especially .gtoreq.80%
by total weight of the composition. In theory, the solvent-based
composition can be 100% solids due to the relatively low molecular
weight of the polymer component. In practice, the upper limit for
the solids content of the solvent-based compositions of the
invention is usually from 95% to 100% by weight of the
composition.
[0225] Surprisingly coatings formed from the high solids solvent
based compositions of the invention have a short dust free time,
are quickly resistant to blocking and damage and can be readily
sanded shortly after application. These useful properties are
generally not seen in conventional autoxidisable paints with a high
solids content.
[0226] Both the aqueous and solvent-based coating compositions of
the invention are particularly useful as (or for providing the
principle component of) coating formulations (i.e. compositions
intended for application to a substrate without further treatment
or additions thereto). Examples of coating compositions are
protective or decorative coating compositions (for example paint,
lacquer or varnish). To prepare a coating compositions an initially
prepared composition optionally may be further diluted with water
and/or organic solvents, and/or combined with further ingredients
or may be in more concentrated form by optional evaporation of
water and/or organic components of the liquid medium of an
initially prepared composition.
[0227] An organic solvent may optionally be added before, during
and/or after the polymerisation process for making the
autoxidisable vinyl polymer to control the viscosity. Examples of
solvents include water-miscible solvents such as propylene glycol
based solvents, especially propylene glycol mono methyl ether and
dipropylene glycol mono methyl ether and glycol ethers such as
butyldiglycol. Optionally no organic solvents are added.
[0228] A co-solvent, as is well known in the coating art, is an
organic solvent employed in an aqueous composition to ameliorate
the drying characteristics thereof, and in particular to lower its
minimum film forming temperature. The co-solvent may be solvent
incorporated or used during preparation of the autoxidisable vinyl
polymer and/or may have been added during formulation of the
aqueous composition.
[0229] The aqueous composition of the invention may have a
co-solvent content in an amount of at least preferably .gtoreq.2%,
more preferably .gtoreq.3.5% and/or no more than preferably
.ltoreq.15%, more preferably .ltoreq.9% and most preferably
.ltoreq.6% by weight of solids. Most preferably substantially no
co-solvent is used as this gives improved storage stability and a
better ecological profile.
[0230] In general, aromatic or heterocyclic nitrogen-containing
ligands (except pyridine) or aromatic and aliphatic primary and
secondary (di)amines were found to prolong the drying time to a
considerable extent (as reported in Coordination Chemistry Reviews
249 (2005) 1709-1728). An example includes heterocyclic
nitrogen-containing solvents such as N-methylpyrrolidone (NMP) and
N-ethylpyrrolidone.
[0231] Preferably the aqueous coating composition comprises NMP in
an amount of no more than .ltoreq.13%, more preferably .ltoreq.10%,
most preferably .ltoreq.5% and especially .ltoreq.0.5% by weight of
polymer solids.
[0232] Preferably the aqueous coating composition comprises only a
small amount of nitrogen containing molecules with an evaporation
rate .ltoreq.0.1, more preferably .ltoreq.0.05 (as calculated
below), the molecules being aromatic, heterocyclic or aliphatic
primary and secondary di-amines where the weight % of nitrogen is
.gtoreq.5% and more preferably .gtoreq.10%.
[0233] Preferably such nitrogen containing molecules are present in
the aqueous coating composition in an amount.ltoreq.13%, more
preferably .ltoreq.10%, most preferably .ltoreq.5% and especially
.ltoreq.0.5% by weight of polymer solids.
[0234] Values for evaporation rates were published by Texaco
Chemical Company in a bulletin Solvent Data; Solvent Properties
(1990). These values are relative to the evaporation rate of
n-butyl acetate for which the evaporation rate is defined as 1.00.
Determination of evaporation rates of solvents not listed in this
bulletin is as described in ASTM D3539. Co-solvents with low
evaporation rates give undesired effects in the final coatings
resulting in slow hardness development acting as a plasticizer.
[0235] It is preferred to have <16% by weight of polymer solids
of a co-solvent with an evaporation rate between 0.05 and
0.005.
[0236] The aqueous or solvent borne coating compositions of the
invention may be applied to a variety of substrates including wood,
board, metals, stone, concrete, glass, cloth, leather, paper,
plastics, foam and the like, by any conventional method including
brushing, dipping, flow coating, spraying, and the like. They are,
however, particularly useful for providing coatings on wood and
board substrates. The aqueous carrier medium is removed by natural
drying or accelerated drying (by applying heat) to form a coating.
Accordingly in a further embodiment of the invention there is
provided a coating obtainable from an aqueous coating composition
of the present invention.
[0237] The aqueous coating composition of the invention may contain
other conventional ingredients including pigments, dyes,
emulsifiers, surfactants, plasticisers, thickeners, heat
stabilisers, levelling agents, anti-cratering agents, fillers,
sedimentation inhibitors, UV absorbers, antioxidants, dispersants,
reactive diluents (e.g. those described above), waxes, neutralising
agents, adhesion promoters, defoamers, co-solvents, wetting agents
and the like introduced at any stage of the production process or
subsequently. It is possible to include fire retardants like
antimony oxide in the dispersions to enhance the fire retardant
properties.
[0238] Preferably when the aqueous composition is formulated as
paint, the composition comprises 2% to 10%, more preferably 3% to
9% of solvent by weight of the total paint composition. Preferably
at least 50%, more preferably .gtoreq.80%, most preferably
.gtoreq.95% by weight of the total solvent are solvent(s) having an
evaporation rate (as defined herein) higher than 0.012, more
preferably from 0.018 to 0.25, most preferably lower than 0.21.
[0239] Preferably the aqueous coating composition when coated onto
a substrate after 24 hrs of drying forms a coating which is water
resistant (for example measured in the tests described herein) for
30 minutes, more preferably for 1 hour and most preferably for 3
hours.
[0240] Preferably the aqueous coating composition when coated onto
a substrate after 24 hrs of drying forms a coating which is block
resistant at room temperature with a rating of 3 or more and more
preferably the coating is block resistant at 52.degree. C. with a
rating of 3 or more.
[0241] In an embodiment of the invention there is provided an
aqueous autoxidisable coating composition with reduced telegraphing
comprising an autoxidisable vinyl polymer obtained by a process
according to the invention; said composition comprising: [0242] i)
33% to 65% of the autoxidisable vinyl polymer; [0243] ii) 0 to 20%,
more preferably 0 to 15%, most preferably 0 to 10% and especially 0
to 5% of co-solvent; and [0244] iii) 15% to 58% of water; [0245]
where all percentages are by weight of the total composition and
i)+ii)+iii)=100%.
[0246] In another embodiment of the invention there is provided an
aqueous autoxidisable coating composition with reduced telegraphing
comprising an autoxidisable vinyl polymer obtained by a process
according to the invention; said composition comprising: [0247] i)
20% to 45%, preferably 20% to 40%, of TiO.sub.2; [0248] ii) 20% to
45%, preferably 25% to 40%, of the autoxidisable vinyl polymer;
[0249] iii) 0 to 10%, preferably 0 to 5%, of co-solvent; [0250] iv)
0.1% to 3% of thickener solids; [0251] v) 0 to 10%, preferably 0 to
5%, of dispersing agent; and [0252] vi) 20% to 60% water; [0253]
where all percentages are by weight of the total composition; and
[0254] i)+ii)+iii)+iv)+v)=100%.
[0255] In particular, the aqueous coating compositions of the
invention and formulations containing them advantageously include a
drier salt(s). Drier salts are well known to the art for further
improving curing in unsaturated film-forming substances.
[0256] Generally speaking, drier salts are metallic soaps, i.e.
salts of metals and long chain carboxylic acids. It is thought that
the metallic ions effect the curing action in the film coating and
the fatty acid components confer compatibility in the coating
medium. Examples of drier metals are cobalt, manganese, zirconium,
lead, neodymium, lanthanum and calcium. The level of drier salt(s)
in the composition is typically that to provide an amount of
metal(s) for example from 0.01 to 0.5% by weight of autoxidisable
vinyl polymer.
[0257] Drier salts are conventionally supplied as solutions in
solvents for use in solvent-borne alkyd systems. They may, however,
be used quite satisfactorily in aqueous coating compositions since
they can normally be dispersed in such systems fairly easily. The
drier salt(s) may be incorporated into the aqueous coating
composition at any convenient stage. For example the drier salt(s)
may be added prior to dispersion into water. Drier accelerators may
be added to the drier salts. Suitable drier accelerators include
2,2'-bipyridyl and 1,10-phenanthroline.
[0258] If desired the aqueous dispersion of the invention can be
used in combination with other polymer dispersions or solutions
which are not according to the invention.
[0259] If compositions of the invention comprise vinyl polymers
other than the autoxidisable vinyl polymers described herein, such
other vinyl polymers are present in the composition in an amount no
more than .ltoreq.35%, more preferably .ltoreq.20%, most preferably
.ltoreq.10% and especially .ltoreq.4% by weight of the total vinyl
polymer solids present.
[0260] Preferably less then or equal to 10% and more preferably
.ltoreq.5% of the autoxidisable vinyl polymer solids comprise vinyl
polymers that are covalently bound to a fatty acid, where the
covalent bond is generated through a grafting reaction of a
propagating vinyl radical onto the unsaturated fatty acid. In the
latter case the fatty acid can either be a free unsaturated fatty
acid or an unsaturated fatty which is part of a polymeric
structure. Most preferably there is no grafting of vinyl monomer to
fatty acid.
[0261] Preferably the coating composition of the invention is a one
component system, meaning that preferably no additional
cross-linking agents, like for instance polyaziridines,
polycarbodiimides, polyisocyanates or melamines are added to the
coating composition, prior to the application of the coating to a
substrate.
[0262] Preferably the coating composition is free from
photoinitiators and is cured without the use of radiation curing
equipment.
[0263] A further aspect of the invention provides a coating
obtained and/or obtainable by a coating composition of the
invention and having a telegraphing value (as defined herein) of
less than 10 gloss units.
[0264] Another aspect of the invention provides a substrate coated
with a coating of the invention.
[0265] A still other aspect of the invention provides a method of
coating a substrate comprising the steps of i) applying a coating
composition of the invention to the substrate; ii) drying the
substrate to form a coating thereon; where the coating has a
telegraphing value (as defined herein) of less than 10 gloss
units.
[0266] Yet another aspect of the invention provides use of an
autoxidisable vinyl polymer and/or a coating composition of the
invention for the purpose of obtaining coatings having a
telegraphing value (as defined herein) of less than 10 gloss
units.
[0267] A still yet other aspect of the invention provides a method
of manufacture of an autoxidisable vinyl polymer and/or a coating
composition of the invention for the purpose of obtaining coatings
having a telegraphing value (as defined herein) of less than 10
gloss units.
[0268] Many other variations embodiments of the invention will be
apparent to those skilled in the art and such variations are
contemplated within the broad scope of the present invention.
Further aspects of the invention and preferred features thereof are
given in the claims herein.
[0269] The present invention is now illustrated by reference to the
following non-limiting examples. Unless otherwise specified, all
parts, percentages and ratios are on a weight basis. The prefix C
before an example denotes that it is comparative.
[0270] The term "working" means that the example is according to
the invention. The term "non-working" means that it is not
according to the invention (i.e. comparative).
[0271] Various registered trademarks, other designations and/or
abbreviations are used herein to denote some of ingredients used to
prepare polymers and compositions of the invention. These are
identified below by chemical name and/or trade-name and optionally
their manufacturer or supplier from whom they are available
commercially. However where a chemical name and/or supplier of a
material described herein is not given it may easily be found for
example in reference literature well known to those skilled in the
art: such as: `McCutcheon's Emulsifiers and Detergents`, Rock Road,
Glen Rock, N.J. 07452-1700, USA, 1997 and/or Hawley's Condensed
Chemical Dictionary (14th Edition) by Lewis, Richard J., Sr.; John
Wiley & Sons.
`AIBN` denotes azobisisobutyronitrile; `Additol VXW4940` denotes
the drying pigment commercially available from Elementis under this
trade name; `Atlas G5000` denotes the non-ionic polyalkylene glycol
ether available commercially from Uniqema under this trade
designation; `BA` denotes n-butyl acrylate; `3,5-BHT` denotes
3,5-di-tert-butyl-4-methylphenol (also known as butyl hydroxy
toluene); `BMA` denotes n-butyl methacrylate; `CoF` denotes the
catalyst Co II (bis 4,4'-dimethylbenzil dioxime) diborondifluoride,
as described in EP1742973-A, US2007219328 and WO2005105855;
`Dehydran 1293; denotes a solution of a special modified
polydimethyl siloxane defoamer that is commercially available from
Cognis under this trade name; `Disperbyk 190" denotes that a
solution of a high molecular weight block copolymer with pigment
affinic groups that is a dispersing additive for pigments that is
commercially available from BYK Chemie under this trade name; `Dow
PnP` denotes that propylene glycol n-propyl ether mixture
commercially available from Dow Chemicals under the trade name
Dowanol PnP; `dtAP` denotes di-tert-amylperoxide; `dtBP` denotes
di-tert-butylperoxide; `FES77` denotes the dispersant which is a
sodium salt of a fatty alcohol glycol ether sulphate and is
available commercially from Cognis under the trade name Disponil
FES 77; `FES993` denotes the dispersant which is a sodium salt of a
fatty alcohol glycol ether sulphate and is available commercially
from Cognis under the trade name Disponil FES 993 IS; `GMA` denotes
glycidyl methacrylate; `HHPA` denotes hexahydro phthalic anhydride;
`Kronos 2190` denotes a titanium dioxide pigment commercially
available from Kronos under this trade name; `MMA` denotes methyl
methacrylate; `NASA` denotes methane sulphonic acid; `NuCa10`
denotes the pigment (10% by weight of a calcium carboxylate in a
hydrocarbon solvent) available commercially from Rockwood Pigments
under the trade designation Nuodex calcium 10; `NuCo10` denotes the
pigment (10% by weight of a cobalt carboxylate in a solvent of
dearomatised kerosene and methoxy propoxy propanol) available
commercially from Rockwood Pigments under the trade designation
Nuodex cobalt 10; `NuZr18` denotes the pigment (18% by weight of a
zirconium carboxylate in a in a solvent of dearomatised kerosene)
available commercially from Rockwood Pigments under the trade
designation Nuodex zirconium 18; `PAA` denotes a conventional
polyacrylic acid with weight average molecular weight (M.sub.w) of
from 200-250 kDalton which has been prepared by the applicant;
`PVC` denotes polyvinyl chloride `Sefose` denotes a soyate made
from partially hydrogenated soybean oil which is commercially
available from P&G Chemicals under the trade name Sefose
1618SC, `Sun-FA` denotes sunflower fatty acid; tBP` denotes
tert-butyl peroxide `tBPD` denotes t-butyl peroxybenzoate `TEA`
denotes triethyl amine; [0272] `THF` denotes tetrahydrofuran; and
`TRAP` denotes triphenyl ethyl phosphonium bromide.
Test Methods:
Standard Conditions
[0273] As used herein, unless the context indicates otherwise,
standard conditions (e.g. for drying a film) means a relative
humidity of 50%.+-.5%, ambient temperature (23.degree.
C..+-.2.degree.) and an air flow of .ltoreq.0.1 m/s.
Particle Size
[0274] The particle sizes given herein are the size of a weight
averaged particle and are quoted as a linear dimension which is a
particle diameter as the particles can be considered to be
essentially spherical. Weight average particle size may be measured
using a scanning/transmission electron microscope and photon
correlation spectroscopy.
Iodine Number
[0275] The iodine value (also referred to herein as iodine number)
is a measure of the amount of ethylenic unsaturated double bonds in
a sample and increases with a greater degree of unsaturation.
Iodine value may be defined according to DIN 53241-1 as the
quotient of that mass m.sub.I of iodine which is added on to the
olefinic double bonds, with decolorisation, of a sample to be
analysed and the mass m.sub.B of this sample (mass of the solid in
the sample in the case of solutions or dispersions). Iodine values
may be quoted either in units of centigrams of iodine per gram of
sample (cg I.sub.2/g) or in units of grams of iodine per 100 gram
of sample (g I.sub.2/100 g). Standard methods for analysis may be
used such as for example ASTM D5768-O.sub.2 (2006) and DIN 53241.
One common method (and that used to measure the iodine values given
herein) is the Wjjs method in which iodine absorption is determined
by titrating unreacted reagent with sodium thiosulfate and the
iodine value is then calculated as follows:
Iodine value = ( 12.69 ) .times. ( ml of thiosulfate ) .times. (
normality ) mass of sample ( g ) ##EQU00001##
Telegraphing
[0276] Two types of PVC substrates are used to determine the degree
of telegraphing of an unpigmented coating comprising the
autoxidisable resin:
[0277] The first PVC type is the 2 mm thick rough PVC substrate
with a well defined and uniform rough surface that is available
commercially from Vink Kunststoffen B. V (Didam, Holland) under the
trade name Vikupor white PVC film type JD11. An area of
1.9.times.2.5 mm of the substrate surface is analysed with a Wyko
optical profilometer NT1100 at a magnification of 2.5 to give
R.sub.z=25 .mu.m.+-.5 .mu.m. R.sub.z denotes the `ten-point
height`, which is the average of the five greatest peak-to-valley
separations in the scanned area, and is regarded as a general value
for surface roughness. The second PVC type is a 3 mm thick smooth
PVC substrate with a well defined smooth surface that is also
available commercially from Vink Kunststoffen under the trade name
Vikunyl white PVC film glossy type 206221. R.sub.z=1 .mu.m.+-.0.25
.mu.m. (measured as for rough PVC).
[0278] The unpigmented coating comprising (optionally comprising
flow and wetting agents and thickeners if needed) is cast on both
PVC substrates (rough and smooth) and a smooth and defect free film
is obtained, resulting in a theoretical dry film thickness between
52 .mu.m.+-.6 .mu.m. The film is dried under standard conditions
for 24 hours and the gloss is measured at a 20.degree. angle. This
gloss measurement is repeated after 4 days, 7 days and 14 days. The
difference in gloss readings between the films on rough and smooth
PVC is a quantitative measure of the extent to which the rough
surface of the PVC is telegraphed to the surface of the dried
coating. The smaller the difference in these gloss values, the
smaller the degree of telegraphing and the better the coating hides
the substrate roughness.
[0279] Also the absolute value for gloss reading on rough PVC
should not decrease significantly in time so that the reduced
telegraphing is maintained.
Drying Time:
[0280] To test the dust-free and tack-free drying times of the
compositions prepared in the Examples as described below, the
compositions are formulated and applied to a glass plate at a wet
film thickness of 80 .mu.m. Tests for drying times are performed at
regular time intervals under standard conditions.
Dust-Free Time:
[0281] The dust-free time (DFT) is determined by dropping a piece
of cotton wool (about 1 cm.sup.3 i.e. 0.1 g) on to the drying film
from a distance of 25 cm. If the piece of cotton wool can
immediately be blown from the substrate by a person without leaving
any wool or marks in or on the film, the film is considered to be
dust-free.
Tack-Free Time:
[0282] The tack-free time (TFT) is determined by placing a piece of
cotton wool (about 1 cm.sup.3, 0.1 g) on the drying film and
placing a weight of 1 kg onto the piece of cotton wool (for 10
seconds). If the piece of cotton wool can be removed from the
substrate by hand without leaving any wool or marks in or on the
film, the film is considered to be tack-free.
Blocking Test
[0283] A 100 .mu.m thick wet film is cast on a Leneta chart and
dried for 24 hours under standard conditions. Resistance to
blocking is determined using a block tester, where pairs of the
coated test charts are placed with the film coatings face to face
and left at ambient temperature for 4 hours or left at 52.degree.
C. for 2 hours with a pressure of 250 g/cm.sup.2. After cooling to
ambient temperature (if applicable), the test charts are peeled
apart and the degree of block resistance is assessed, ranging from
0 (very poor blocking resistance) to 5 (excellent blocking
resistance). When the test charts can be peeled apart using minor
force without damaging the surface of the film, blocking is
assessed as 3.
Measurement of Film Yellowing:
[0284] The yellowing of a coating exposed to daylight or darkness
for a specified time period is determined using a Dr Lange
Spectropen. The equipment is calibrated to the defined values of
the calibration plate and then the b-value is measured according to
the CIE L, a, b method. The dark-yellowing is defined as the
increase in the yellowness (Ab) of the coating during storage at
52.degree. C., in the dark for 21 days.
Molecular Weight Determination:
[0285] Gel permeation chromatography (GPC) analysis for the
determination of polymer molecular weights are performed on an
Alliance Waters 2695 GPC with three consecutive PL-gel columns
(type Mixed-B, I/d=300/7.5 mm) using tetrahydrofuran (THF, HPLC
grade, stabilized with 3,5-di-tert-butyl-4-hydroxytoluene [BHT],
preferably with 1.0 vol. % acetic acid) as the eluent at 1
cm.sup.3/min and using an Alliance Waters 2410 refractive index
detector. A set of polystyrene standards (analysed according to DIN
55672) are used to calibrate the GPC. Samples corresponding to
about 16 mg of solid material are dissolved in 8 cm.sup.3 of THF.
The samples are regularly shaken and dissolved for at least 24
hours for complete "uncoiling" and placed on the auto-sampling unit
of the Alliance Waters 2695. The injection volume is 150 .mu.L and
the temperature of the column oven is established at 35.degree.
C.
GLASS TRANSITION TEMPERATURE (T.sub.G)
[0286] The T.sub.g is measured by DSC using the TA Instruments DSC
Q1000 with standard TA Instruments alumina cups of 50 .mu.l. The
flow rate is 50 ml/min of nitrogen and the sample is loaded at
ambient temperature. The sample is cooled until it reached an
equilibrium temperature of -90.degree. C. and then heated at a rate
of 10.degree. C./min to 100.degree. C., kept for 5 minutes at
100.degree. C., cooled to -90.degree. C. at a rate of 20.degree.
C./min, kept for 5 minutes at -90.degree. C. and subsequently
heated at a rate of 10.degree. C./min to 100.degree. C.
[0287] The T.sub.g values in the Examples and Tables herein are the
midpoint as measured by DSC as described above.
Water Resistance:
[0288] A 100 .mu.m thick wet film is cast on a Leneta chart and
dried for 24 hours under standard conditions. Then three drops of
water are placed on the film and one drop of water is removed after
30 minutes, one after 1 hour and one after 3 hours. The water
resistance is assessed immediately after removal of the water and
then after 24 hours. The rating for water resistance is from:
0=very poor, dissolved; 3=acceptable; 5=excellent, no damage of the
coating.
Gloss Measurement Method:
[0289] Gloss measurements are carried out on a BYK Gardner
micro-TRI-gloss 20-60-85 gloss meter in accordance with ASTM
D523-89.
[0290] The examples herein are prepared by the following common
method modified as indicated in the tables with reference to each
of the alphanumeric labels given below.
Common Method
Step (A1) Preparing an Epoxy Functional Vinyl Polymer (Alternative
1)
[0291] In one alternative (A1) of step a round bottom reaction
vessel (VOL) equipped with a stirrer, baffle and cooler, is loaded
with water (a), Na.sub.2SO.sub.4 (b) and PAA (c) in a nitrogen
atmosphere. The mixture is neutralized with NaOH until the pH is
>8 and the mixture temperature is brought to 60.degree. C. A
homogeneous mixture of MMA (d), BMA (e), GMA (f), AIBN (g) and CoF
(h) is transferred to the reactor and the reaction temperature is
brought to 80.degree. C. After time t1 a mixture of FES993 (i) and
water (j) is added to the reactor. After time t2 the temperature is
raised to 85.degree. C. and is held there for 60 minutes. The
reaction vessel is then cooled to ambient temperature and polymer
beads are obtained that are washed and dried for use in the next
step (B).
[0292] The polymer obtainable in this step (A1) is characterised as
follows:
M.sub.n=k, M.sub.w=l, PDi=m,T.sub.g=n.
Step (A2) Preparing an Epoxy Functional Vinyl Polymer (Alternative
2)
[0293] A round bottom, optionally high pressure where specified
herein, reactor (VOL'), equipped with stirrer and cooler, is loaded
under nitrogen with a solvent (SOL1, a') and heated to T'1. A
homogeneous mixture of styrene (b'), GMA (c'), BA (dd'), BMA (d'),
d-BP (e') and t-BPB (f') is fed to the reactor using a pump over
time t'1 at pressure (g').
[0294] Optionally after the ingredients have been added to the
reactor the pump is rinsed with more solvent (SOL1, h'), and the
reactor is then heated to T'2 for time t'2, cooled to T'3 and then
dtAP (i') is added in small portions over time t'3.
[0295] The mixture is held at 140.degree. C. for time t'4 and then
the reactor is cooled to ambient temperature. Optionally further
solvent is added (SOL1, j')
[0296] The polymer obtainable in this step (A2) is characterised as
follows:
Solid content=k',M.sub.n=M.sub.w=m',PDi=n'
Step (B) Preparing an Aqueous Autoxidisable Vinyl Polymer
[0297] An amount (p) of vinyl polymer prepared as described in the
common method step (A1 or A2) above is dissolved in a solvent
(SOL2, q). SunFA (r) and TRAP (s) are added to the resulting
solution to form a mixture which is heated at 120.degree. C. under
nitrogen. The reaction is continued until an acid number (AN) (t)
is reached.
[0298] In an optional further step further SunFA (ta) and MSA (tb)
are added, the mixture is again heated to 120.degree. C. under a
nitrogen atmosphere and esterification is continued until an acid
number (AN) (tc) is reached.
[0299] SOL2 is removed by distillation under reduced pressure and
the polymer obtained is characterised as follows:
M.sub.n=u,M.sub.w=v,PDi=w,T.sub.g=x.
Step (C1) Dispersing Vinyl Polymer Obtainable from Step
(B)--Alternative 1
[0300] To an amount (y) of a polymer prepared as described in the
common method step (B) is added Atlas G5000 (z), ALES (aa) and
Ingredientl (IGD1, ab). Then water (ac) is added slowly to form a
dispersion which is stirred for time t5 before being stored under
nitrogen. The dispersion is characterised as follows:
solids content=ad,pH=pH2,ND.times.AV=ae
Step (C2) Dispersing Vinyl Polymer Obtainable from Step
(B)--Alternative 2
[0301] To an amount (y') of a polymer prepared as described in the
common method step (B) (z' solids dissolved in solvent SOL3) is
added HHPA (aa'). The mixture is held at a temperature T6 until
substantially all the anhydride has reacted as determined from the
Infra Red spectrum of the reaction mixture. The anhydride groups
typically show two absorptions at 1785 cm.sup.-1 and 1865
cm.sup.-1, which disappear once the reaction is complete and a new
ester carbonyl absorption appears at 1740 cm.sup.-1. The SOL3 is
then removed by distillation under reduced pressure to obtain a
fatty acid functional acrylic (FA acrylic) with acid number (AN)
(ab'). Added to the FA acrylic (ac') are Ingredient2 (IGD2, ad')
and TEA (ae') followed by water (af') to obtain an aqueous
composition characterised as follows:
solids
content=ag';pH=pH3,T.sub.g=ah',M.sub.n=ai',M.sub.w=aj',PDi=ak'&(N-
D.times.AV)=al'
[0302] Step (C3) Dispersing Vinyl Polymer Obtainable from Step
(B)--Alternative 3
[0303] To an amount (y'') of a polymer prepared as described in the
common method step (B) (z'' solids dissolved in solvent SOL3') is
added NuCal 0 (aa'') and NuCo10 (ab'') and NuZr18 (ac'') to obtain
the product.
[0304] All the examples were prepared as described in the common
methods with reference to the data in the Tables (as shown below).
In the Tables NM indicates a parameter is not measured and NA that
that parameter is not applicable to that example. Some examples may
be prepared by more than one step at each stage (A, B or C as
indicated in the Tables), so [A1 and A2] and [C1, C2 and/or C3] are
not always alternatives but may also be combined.
TABLE-US-00001 Common Method Data in Table(s) A1 1 (Process), 2
(Characterisation) A2 3 (Characterisation), 4a & 4b (Process) B
5 (Process & Characterisation) C1 6 (Process &
Characterisation C2 7 (Process), 8 (Characterisation) C3 9 (Process
& Characterisation)
[0305] As almost all of the products from step C are not
neutralised (all except Ex8c) the ND is 0 so ND.times.AV is 0. The
value of ND.times.AV for Ex 8c is given in Table 8.
TABLE-US-00002 TABLE 1 Common method Step A--Alternative 1--Process
conditions Item Vessel Rtn. Add. size Water Na.sub.2SO.sub.4 PAA
MMA BMA GMA AIBN CoF time FES993 water time Units litres grams
grams grams Grams grams grams grams grams mins grams grams mins
Label Ex VOL a b c D e f g h t1 I j t2 C1a 2 867.8 1.59 0.79 381.59
0 254.39 4.77 0.01 45 0.53 79.5 15 C2a 2 867.8 1.59 0.79 190.79
159.00 286.19 4.77 0.006 60 0.53 79.5 15 Ex1a 2 867.8 1.59 0.79
190.17 127.19 317.99 4.77 0.064 90 0.53 79.5 10 Ex2a 10 4911.75
9.00 4.47 1076.36 719.90 1799.82 27.00 0.36 105 3.00 449.97 10 Ex3a
10 4932.00 8.94 4.44 1073.21 715.48 1788.69 26.83 0.36 90 2.98
447.19 10 Ex4a 2 867.8 1.59 0.79 190.17 127.19 317.99 4.77 0.064 90
0.53 79.5 10 C4a 10 5045.2 12.60 4.50 2160.00 0 1440.00 27.00 0.288
45 6.00 400.00 15 C5a 2 867.8 1.59 0.79 190.8 159.0 286.2 4.77
0.006 45 0.53 79.5 15 Ex7a 2 867.8 1.59 0.79 190.17 127.19 317.99
4.77 0.064 90 0.53 79.5 10 Ex8a 10 4911.75 9.00 4.47 1076.36 719.90
1799.82 27.00 0.36 105 3.00 449.97 10 Ex9a 10 4932.00 8.94 4.44
1073.21 715.48 1788.69 26.83 0.36 90 2.98 447.19 10 Ex10a 10
4932.00 8.94 4.44 1073.21 715.48 1788.69 26.83 0.36 90 2.98 447.19
10
TABLE-US-00003 TABLE 2 Common method Step A - Alternative 1 -
Characterization of product Item M.sub.n M.sub.w PDi T.sub.g Units
g/mol g/mol none .degree. C. Label Ex k l m n C1a 4991 22107 4.43
97 C2a 19048 39989 2.1 71 Ex1a 1736 3589 2.07 24 Ex2a 2221 4943
2.23 37 Ex3a 2081 4256 2.04 34 Ex4a 1736 3589 2.07 24 C4a 1977 4783
2.4 49 C5a 19048 39989 2.10 71 Ex7a 1736 3589 2.07 24 Ex8a 2221
4943 2.23 37 Ex9a 2081 4256 2.04 34 Ex10a 2081 4256 2.04 34
TABLE-US-00004 TABLE 3 Common method Step A - Alternative 2 -
Characterization of product Item Solids M.sub.n M.sub.w PDi Units %
g/mol g/mol none Label Ex k' l' m' n' C3a NM 3167 7497 2.4 Ex5a
60.0 2548 7720 3.0 Ex6a 58.4 1593 3982 2.5
TABLE-US-00005 TABLE 4a Common method Step A--Alternative
2--Process conditions Item High Reactor pressure Solvent Solvent
Mix feed vessel name amount temp Stryene GMA BA BMA dtBP tBPB time
Pressure Units none None grams .degree. C. grams Grams grams grams
grams grams hours bar Label Ex none SOL1 a' T'1 b' c' dd' d' e' f'
t'1 g' C3a NO Xylene 219.99 140 319.59 213.06 0 0 27.33 20.03 4 1
Ex5a YES Toluene 500.0 150 0 475.3 475.3 0 38.0 0 2.5 2.8 Ex6a YES
Toluene 500.0 150 0 475.3 0 475.3 38.0 0 2.5 2.8
TABLE-US-00006 TABLE 4b Item More Reactor heat Further reaction
Reactor cool dtAP Hold Further Solvent temp time temp dtAP time
time Solvent Units Grams .degree. C. mins .degree. C. grams hours
mins grams Label Ex h' T'2 t'2 T'3 i' t3 t'4 j' C3a 0 NA 0 NA 0 0
120 0 Ex5a 20.0 150 30 140 38.0 2 90 101.04 Ex6a 20.0 150 30 140
38.0 2 90 101.04
TABLE-US-00007 TABLE 5 Common method Step B Item Polymer Solvent
Solvent from A name amount SunFA TRAP AN SunFA MSA AN M.sub.n
M.sub.w PDi T.sub.g Units grams none grams grams grams mg KOH/g
grams grams mg KOH/g g/mol g/mol none .degree. C. Label Ex p SOL2 q
r s t ta tb tc u v w x C1b 500.0 Toluene 300.34 397.06 3.97 5.9 NA
NA NA 5856 43337 7.4 26 C2b 500.0 Toluene 344.45 531.33 5.31 14.0
NA NA NA 44460 233091 5.24 4 C3b 935.2 Toluene 0 450.0 4.5 13.6 NA
NA NA 3383 13533 4.0 -14 Ex1b 500.0 Toluene 332.59 492.85 4.93 5.7
NA NA NA 2736 7662 2.8 -12 Ex2b 550.0 Toluene 365.85 542.13 5.42
10.2 NA NA NA 2531 11052 4.4 -13 Ex3b 1000.0 Toluene 665.18 985.70
9.86 8.9 NA NA NA 3601 9044 2.51 -16 Ex4b 500.0 Toluene 332.59
492.85 4.93 5.7 NA NA NA 2736 7662 2.8 -12 Ex5b 583.3 Toluene 0
342.0 3.42 4.3 NA NA NA 2331.95 19122 8.2 -44 C4b 210.0 Xylene
213.10 50.00 0.50 12.8 NA NA NA 1924 5581 2.9 31 C5b 500.0 Toluene
344.45 531.3 5.31 14.0 NA NA NA 44460 233091 5.24 4 Ex6 583.3
Toluene 0 342.0 3.42 0.1 NA NA NA 2014 9062 4.5 -35 Ex7b 500.0
Toluene 332.59 492.85 4.93 5.7 NA NA NA 2736 7662 2.8 -12 Ex8b
550.0 Toluene 365.85 542.13 5.42 10.2 NA NA NA 2531 11052 4.4 -13
Ex9b 550.0 Toluene 365.85 542.13 5.42 10.2 96.84 2.53 8.0 3088
23465 7.6 -13 Ex10b 550.0 Toluene 365.85 542.13 5.42 10.2 96.84
2.53 8.0 2593 21001 8.1 -14 When q is 0 this means solvent is
present from the previous step (which is removed as described) but
no more solvent added in this step
TABLE-US-00008 TABLE 6 Common method Step C--Alternative 1 Item
Polymer Atlas Ingredient Ingredient stir from B G5000 FES77 Name
Amount water time solids pH Units grams grams grams None grams
grams mins % none Label Ex y z aa IGD1 ab ac t5 ad pH2 Type C1c
97.0 2.43 11.76 None 0 76.6 30 55 5.4 W C2c 100.8 2.52 12.22 Dow
PnP 10.08 98.03 30 52.4 6.3 W C3c 112.0 2.8 13.58 None 0 88.5 30 45
5.0 W Ex1c 117.0 2.93 14.18 Dow PnP 23.90 118.89 30 45 6.0 W Ex2c
100.0 2.50 12.12 Sefose 20.00 95.38 30 55 5.9 W Ex3c 500.0 12.50
60.61 None 0 395.08 30 55.6 6.6 W Ex5c 100.07 2.50 12.13 None 0
79.07 30 55 5.5 W Ex 8c 80 0 0 Sefose 20 0 0 NM NM W
TABLE-US-00009 TABLE 7 Common method Step C--Alternative 2--Process
conditions Item Polymer Solvent hold FA Ingredient Ingredient from
B Solids Name HHPA temp AN acrylic Name Amount TEA Water Units
grams % None grams .degree. C. mg KOH/g grams None grams grams
Grams Label Ex y' z' SOL3 aa' T6 ab' ac' IGD2 ad' ae' af' Ex4c
340.0 75 Toluene 44.19 110 59.4 300.0 DowPnP 75.0 28.9 453.0 Ex10c
300 NM Toluene 22.95 110 38.0 0 0 0 0 0
TABLE-US-00010 TABLE 8 Common method Step C--Alternative
2--Characterization of product Item solids pH T.sub.g M.sub.n
M.sub.w PDi ND .times. AV Units % none .degree. C. g/mol g/mol none
mg KOH/g Label Ex ag' pH3 ah' ai' aj' ak' al' Type Ex4c 35 7.8 -1
1769 8128 4.52 53.5 W Ex10c NM NM -14 2593 21001 8.1 0 S
TABLE-US-00011 TABLE 9 Common method Step C--Alternative 3 Item
Polymer from B Solids Solvent Name NuCa10 NuCo10 NuZr18 Units grams
% None grams grams grams Label Ex y' z' SOL3' aa'' ab'' ac'' Type
C4c 100 55 None 0.83 0.25 1.20 S C5c 100 56 None 0.83 0.25 1.20 S
Ex6c 100 78 white spirit 1.18 0.35 1.70 S Ex7c 100 70 white spirit
1.06 0.31 1.52 S Ex8c* 100 75 Xylene 1.14 0.33 1.63 S Ex9c 100 70
white spirit 1.06 0.31 1.52 S Ex10c** 100 80 white spirit 1.21 0.35
1.74 S *To prepare Ex 8c the polymer used in step C3 was the
mixture Ex8c obtained from step C1 *To prepare Ex 10c the polymer
used in step C3 was Ex10c obtained from step C2
In each of Tables 6, 8 and 9 which characterize the final product
(from step C) for each example herein the column heading "Type"
indicates whether the example is a water based (W), or solvent
based (S) system.
[0306] The properties of coatings made from the examples and
pigment pastes PP1 prepared by mixing the ingredients in the
respective weight ratios indicated Table 9 are also tested and the
results given in Tables 10 and 11 below.
TABLE-US-00012 TABLE 10 Composition pigment paste PP1 Compound
Pigment paste PP1 Water 4.8 Dehydran 1293 0.4 Disperbyk 190 0.7
Kronos 2190 24.1
TABLE-US-00013 TABLE 11 Application properties of water-based
binders Example Ex 1 Ex 2 C1 C2 C3 Ex 1 pigment Ex 2 pigment Ex 3
Ex 4 Ex 5 Binder (wt %) 100 100 100 100 70 100 70 100 100 100
Particle size [nm] 985 555 370 365 n.a. 320 n.a. 380 <50 354
Additol 2.2 2.2 1.8 1.8 1.4 2.2 1.4 2.2 1.4 2.2 VXW4940/water 1:1
PP1 (wt %) -- -- -- -- 30 -- 30 -- -- -- DFT [hr] 1 0.25 1.5 1 2 1
2 1 2 2 TFT [hr] 2 0.75 7 3 4 2 3.5 2 2.5 3.5 G(s) 81.6 73.5 70.1
78.2 76.6 73.8 79.7 82.4 83.2 78.4 G(r) 40.0 19.1 59.3 77.6 72.7
72.6 77.3 78.3 79.0 72 Telg. 41.6 54.4 10.8 0.6 3.9 1.2 2.4 4.1 4.2
6.4 G decay (4 d) 1.9 3.4 10.1 4.2 2.4 0.8 0.2 2.1 6.7 9.8 G decay
(7 d) 1.0 3.6 13.5 4.6 4.4 5.7 3.9 4.3 7.5 13.9 G decay (14 d) 4.6
4.2 26.3 9.3 4.7 9.4 8.0 9.2 8.9 28.3 Initial yellowness [.DELTA.b]
3.8 3.1 4.5 4.7 1.0 3.4 2.2 3.8 n.d. 3.7 Dark yellowing .DELTA.b
6.6 14.6 21.4 6.1 6.2 5.7 6.9 7.0 n.d. 9.2 3 wks 52.degree. C.
Water resistance 30 min after recovery n.d. n.d. n.d. 5/5 4/5 n.d.
4/5 n.d. n.d. n.d. 1 hr after recovery n.d. n.d. n.d. 4.5/5 3/5
n.d. 3/5 n.d. n.d. n.d. 3 hrs after recovery n.d. n.d. n.d. 4/5 1/5
n.d. 2/5 n.d. n.d. n.d. Blocking 4 hrs at amb. temp. n.d. n.d. n.d.
n.d. 4.5 n.d. 4 n.d. n.d. n.d. 2 hrs at 50.degree. C. n.d. n.d.
n.d. n.d. 4 n.d. 3 n.d. n.d. n.d.
TABLE-US-00014 TABLE 12 Application properties of solvent-based
binders (100% binder) Example C4 C5 Ex 6 Ex 7 Ex 8 Ex 9 Ex 10 DFT
[hr] 0.5 0.25 1.5 1.5 1 1.5 1.5 TFT [hr] 0.5 1 4 1.5 1.5 1.5 4 G(s)
76.9 81.8 82.8 83.3 82.6 82.9 82.9 G(r) 23.0 20.2 81.6 82.6 82.0
81.8 82.1 Telg. 53.9 61.6 1.2 0.7 0.6 1.1 0.8 G decay (4 d) 0.8 1.3
0.3 0.3 0.9 1.6 0.5 G decay (7 d) 2.9 2.2 3.9 1.0 0.1 0.9 0.5 G
decay (14 d) 4.7 4.2 7.4 4.1 2.5 4.3 0.3 Initial yellowness
[.DELTA.b] 2.3 4.0 3.1 2.4 5.3 2.4 6.6 Dark yellowing .DELTA.b 1 3
wks 52.degree. C. 0.8 22.1 17.2 4.3 0.7 4.3 6.5 Key for Tables 11
and 12 `DFT` denotes dust free time defined and measured as
described herein `TFT` denotes tack free time defined and measured
as described herein `G(r)` denotes the initial rough gloss value as
defined herein (measured in gloss units 1 day after film formation)
`G(s)` denotes the initial smooth gloss value as defined herein
(measured in gloss units 1 day after film formation) `Telg.`
denotes the telegraphing value as defined herein in gloss units
(i.e. G(s).sub.- G(r)) `G decay (`n` d)` denotes the gloss decay
value as defined herein after `n` days (i.e. G(r) minus the rough
gloss measured `n` days after film formation).
* * * * *